Physostegia correllii

National Collection of Imperiled Plants

The Center's National Collection of Endangered Plants contains plant material for 788 of the most imperiled native plants. An important conservation resource, the Collection is a backup in case a species becomes extinct or no longer reproduces in the wild. Search the National Collection and view the plant profiles to learn more about these beautiful, imperiled plants.

 

*Abies fraseri 

The Fraser fir is endemic to high elevations in the southern Appalachian Mountains. It is named after John Fraser, the Scottish botanist/explorer who discovered it in the late 18th century. This coniferous evergreen tree grows from 30-80 ft. tall, around 12 inches in diameter, and has a narrow (more)

 

*Abronia ammophila 

Abronia ammophila, a.k.a. the Wyoming sand verbena, is an upright, multi-branched perennial herb that is a member of the Nyctaginaceae family. It was first collected at the mouth of Pelican Creek along the north shoreline of Yellowstone Lake in 1885 by Frank Tweedy, and later named by Greene. (more)

 

*Abronia macrocarpa 

The large-fruited sand verbena is a graceful perennial member of the four o'clock family and is native to sandy areas of East Texas. The stems are ascending to erect, to 50 cm tall. The sand verbena produces among the region's most attractive inflorescences. In spring, head-like clusters of 20-75 (more)

 

*Abronia umbellata ssp. breviflora 

Due to an ironic twist of fate, pink sandverbena was the first North American plant collected and described from west of the Mississippi. Pink sandverbena seeds were first collected at Monterey Bay, CA on a 1786 scientific expedition. The collector, Jean-Nicolas Collignon, was subsequently lost (more)

 

*Abutilon eremitopetalum 

Abutilon eremitopetalum is endemic to the dry forest habitats of Lana`i. Since its discovery in the 1930's, it has always been very rare and has been known only in small, widely scattered colonies. By the early 1980s, the taxon was generally considered extinct. In 1987, 60-70 plants were (more)

 

*Abutilon menziesii 

Abutilon menziesii is a beautiful shrub with velvety light green, heart shaped leaves. Its flowers range from pale pink to maroon and are borne singularly at the base of the leaves. Abutilon menziesii has apparently been uncommon since its discovery in the 1800's, and is currently found in the (more)

 

*Abutilon parishii 

Abutilon parishii has a woody base with herbaceous branches, the branches and petioles densely stellate-tomentose. Plants usually have long, sparsely leaved stems (Shreve and Wiggins 1994). The cordate leaves are extremely velvety and the reverse side is much paler than the green upper leaf (more)

 

*Abutilon sandwicense 

There are three threatened Abutilon species endemic to Hawai’i (U.S. Fish and Wildlife Service [USFWS] 2001). This particular species once occurred along nearly the entire length of the Wai’anae Mountains on the island of O’ahu, Hawaii, but its populations are rapidly declining. In 1998, 14 (more)

 

*Acacia koaia 

Species that belong to the genus Acacia are member of the family Fabaceae, which is also commonly referred to as the legume, or pea, family. There are two Acacia species endemic to Hawai’i. The first, referred to as Acacia koa sensu stricto, is a fairly common Hawaiian tree that is well known for (more)

 

*Acanthomintha duttonii 

San Mateo thornmint is found only in serpentine grassland in a small area south of San Francisco, in San Mateo County, California. This annual herb grows erect up to 20 cm. tall; its leaves are 8-12 mm. long, usually with toothed margins. Bracts in the inflorescence have marginal spines and the (more)

 

*Acanthomintha ilicifolia 

A short aromatic annual, the San Diego thorn mint is primarily found on privately owned land in San Diego County. It produces clusters of white flowers with pink lobes from April to June. Unfortunately, over ninety percent of the available habitat for this species has been lost to development over (more)

 

*Achyranthes splendens var. rotundata 

Achyranthes rotundata is a shrub that ranges in height from 1.5 to 6.5 feet tall. It is covered in short, silvery hears, being inconspicuous flowers in a long (more)

 

*Aconitum noveboracense 

The primary distinctive characteristic of this showy perennial is its large, blue, hood-shaped flowers. A single stem grows from one to four feet in height and may bear several one inch long flowers. The upper sepal is modified into a helmet, which conceals the upper two petals of the flower. (more)

 

*Adiantum viridimontanum 

Adiantum viridimontanum is a slender fern that grows up to 75 cm (2.5 feet) tall. This species can be found in Vermont and Quebec in habitats that have exposed rock, some of which is mined for asbestos. These rocky areas (called serpentine habitat) typically support only sparse vegetation (more)

 

*Aeschynomene virginica 

Sensitive joint-vetch, so-named because its leaves fold slightly when touched, inhabits freshwater tidal marshes along the mid-Atlantic coast. Only 24 populations remain in New Jersey, Maryland, North Carolina, and Virginia, and the species has shrunk substantially from its former distribution, (more)

 

*Agalinis acuta 

The delicate, bright pink blossoms of Agalinis acuta grace the sandplain grasslands of the northeastern United States in late summer. Found on dry, low-nutrient soils, this plant appears to depend upon disturbance (including fire) to persist. Only around a dozen populations remain of some fifty (more)

 

*Agalinis auriculata 

Apparently it's not easy being an annual, disturbance-dependent hemiparasite. But such is the life of the earleaf foxglove, a fall-blooming wildflower that formerly occurred in prairie and prairie-like habitat from New Jersey to Minnesota, south to Texas, Mississippi and Alabama. As an annual that (more)

 

*Agalinis navasotensis 

An annual herb from a few fibrous roots, 2.8-9.0 dm tall. Leaves are thread-like, usually 1.2-3 cm long. Flowers are lavender to rose-purple, bilaterally symetric, pikose externally, usually 1.6-2.5 cm long including flower tube and the five spreading to reflexed lobes. Collected in bloom in the (more)

 

*Agalinis skinneriana 

This rare annual forb is a hemiparasite, meaning that it attains some of its nutrients by attaching its roots to those of other nearby species. Agalinis skinneriana generally occurs in small scattered populations throughout its range, which extends south from Ontario and Ohio to Missouri and (more)

 

*Agave arizonica 

Agave arizonica was first discovered in 1959 in the New River Mountains of Arizona (Gentry 1970, 1982). It has been described as one of the rarest and most beautiful agaves in Arizona. The Arizona agave is a member of a prestigious family of plants, the Agavaceae. Within this family are numerous (more)

 
*Agave delamateri 

 

*Agave eggersiana 

Agave eggersiana is a perennial herb known only from the island of St. Croix of the U.S. Virgin Islands (USFWS 1998a). This species can grow up to seven meters in height and has large, yellow tubular flowers that produce flattened black seeds (USFWS 1998a). A small number of A. eggersiana remain on (more)

 

*Agave parviflora 

Most plants in the genus Agave are monocarpic, meaning that they spend a number of years growing to maturity before they flower once, produce seeds, and then die. While growing, they accumulate a large quantity of sugar and starch in the 'heart tissue' of the plant. These carbohydrates supply the (more)

 

*Agave schottii var. treleasei 

Members of the Agave genus occur natively in arid and tropical regions from the southern USA to northern South America, and throughout the Caribbean (Benson and Darrow 1981, Gentry 1986). More than 200 species are recognized. The name Agave is derived from the Greek and means "noble," referring to (more)

 

*Ageratina luciae-brauniae 

Lucy Braun's snakeroot is closely related to several familiar plant species: thoroughworts, boneset, Joe-pye-weed, and white snakeroot. The last-mentioned, when eaten by cows, was the Midwestern source of the deadly milk sickness, which also plagued early settlers and killed Abraham Lincoln's (more)

 

*Alectryon macrococcus var. auwahiensis 

Alectryon macrococcus is a tree that can grow to 11 meters tall. It has reddish-brown branches and glossy leaves with a netted pattern of veins. Leaves are composed of two to five pairs of egg-shaped leaflets that are slightly asymmetrical. The fruit of this tree provided food for the early (more)

 

*Aletes humilis 

This species is found on granite outcrops and on cliff-sides. This type of habitat occurs nearly everywhere in north-central Colorado, but in over a century of searching, less than a dozen population of this species have been found. Now known from only seven localities on the Front Range of (more)

 

*Aletes macdougalii ssp. breviradiatus 

Herbaceous perennial, arising from an often much-branched, woody root crown; leaves oblong in outline. Flowers May and June.


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*Aliciella formosa 

Aztec gilia is a rare herbaceous perennial from northwestern New Mexico. Diminutive in size, it is only 7-30 cm tall. This perennial can develop a woody base, and has numerous, branched stems. Leaves are entire, 25 mm long, glandular, and sharp-pointed. Flowers are a lovely pinkish-purple, (more)

 

*Allium gooddingii 

Goodding's onion is a delicate perennial with reddish-purple flowers and a pungent onion aroma. It appears after snow melt and blooms from late May to mid-June. It is often hard to locate and identify plants due to heavy grazing by domestic and wild ungulates that reduce the aboveground parts of (more)

 

*Allium munzii 

This elusive wetland perennial is hard to find. Despite producing 10 to 36 white flowers at a time, it only flowers during years with adequate rainfall, an event which doesn't always happen in Southern California. In fact, this species doesn't even produce leaves during the worst drought years, (more)

 

*Alsinidendron trinerve 

There are four threatened Alsinidendron species endemic to Hawai’i (U.S. Fish and Wildlife Service [USFWS] 2001). This species is found only on the island of O’ahu, and its three remaining wild populations are drastically declining. In 1998, 108 plants were recorded by USFWS (USFWS 1998). In (more)

 

*Amaranthus pumilus 

The Seabeach amaranth is endemic to the Atlantic coastal plain beaches, where it is currently found in Maryland, New York, New Jersey, North Carolina, and South Carolina. It historically occurred in nine states, but is now extirpated from the states of Massachusetts, Rhode Island, Delaware, (more)

 

*Ambrosia cheiranthifolia 

The Seabeach amaranth is endemic to the Atlantic coastal plain beaches, where it is currently found in Maryland, New York, New Jersey, North Carolina, and South Carolina. It historically occurred in nine states, but is now extirpated from the states of Massachusetts, Rhode Island, Delaware, (more)

 

*Ambrosia linearis 

It may be surprising to find a rare plant in a genus known for its weeds, but such is the case of the Colorado bursage. Known only from the high plains of eastern Colorado, this ragweed relative is associated with unique, temporary rainwater basins known as playa lakes, as well as other (more)

 

*Amelanchier nantucketensis 

Amelanchier nantucketensis, an endemic of the Atlantic Coast, has a very restricted distribution area (Crow 1985). This species is a low growing, slender shrub that forms large, dense colonies or small clumps by way of producing underground stolons (Seymour 1989). It can be found in sunny, sandy (more)

 

*Amoreuxia gonzalezii 

Herbaceous perennial up to 8 cm tall from a fusiform tuberous rootstock. Leaf blades alternate, long petioled, 3 to 6 cm wide, deeply 5 to 7 parted, dark green above and paler or with scattered dark brown spots beneath. Petals 3 cm long, bright orange-yellow with 1 or 2 brownish-carmine spots (more)

 

*Amorpha crenulata 

Amorpha herbacea var. crenulata, a semi-deciduous shrub, has several flower spikes that range in color from white and orange to blue and purple. The small, dark green leaflets are numerous (25-35) on a reddish branch. Amorpha herbacea var. crenulata is known from the Miami Rock Ridge Pinelands, an (more)

 

*Amorpha ouachitensis 

The Ouachita Mountain indigo is a small attractive shrub that grows to approximately 2 meters in height. The leaves are pinnately compound with broadly elliptical leaflets. The plant blooms from late April to early June. Individual flowers are tiny, but cluster together in the inflorescence, (more)

 

*Amsinckia carinata 

A case of mistaken identity could lead to the extinction of the Malheur Valley fiddleneck. In 1993, Amsinckia carinata was listed as a synonym of the rare, though not endangered Amsinckia vernicosa (the populations are separated by nearly 500 miles (800km)). The decision was based on the (more)

 

*Amsinckia grandiflora 

The large-flowered fiddleneck is a striking annual plant, growing to 50 cm. tall and having bright orange flowers (14-20 mm. long) from April to May in northern California. It is now found in only three populations, one on private rangeland and two on the U.S. Department of Energy's Lawrence (more)

 

*Amsonia grandiflora 

Amsonia grandiflora is a showy herbaceous perennial with milky sap and numerous erect stems arising in a dense clump from a long lived root. The foliage and flowers are entirely glabrous. Leaves are alternate, vary in width, from lanceolate towards the base of the plant, to almost hair-like (more)

 

*Amsonia kearneyana 

Subgenus Sphinctosiphon includes five Arizona species: A. kearneyana, A. jonesii, A. palmeri and A. peeblesii, A. kearneyana was considered as synonomous with A. palmeri (North American Flora 29:129), but Kearney, et al (1960) maintain A. kearneyana based on distinct characteristics of mature (more)

 

*Amsonia tharpii 

Plants are herbaceous perennials from a long woody taproot. They become dormant, dying back to the ground during November and emerging from dormancy during March. Leaves are sessile, linear-lanceolate with rounded tips, about 3 cm long and whorled on stems. Flowers are white, clustered at ends (more)

 

*Ancistrocactus tobuschii 

Tobusch fishhook cactus has attractive yellow flowers which appear in early spring. This beautiful little cactus grows in limestone arroyos in the eastern part of the Edwards Plateau. This is an area that is highly desirable for land development, which is a major threat to the survival of the (more)

 
*Anthericum chandleri 

 

*Apios priceana 

Price's Ground Nut was first collected by Sadie Price in Kentucky in 1896 (USFWS 1993). The plant is an herbaceous, perennial vine that grows from a stout, thick tuber. Apios priceana blooms from mid-June through August, producing clusters of fleshy greenish-white or brownish pink flowers. Fruit (more)

 

*Aquilegia chrysantha var. rydbergii 

This species is the only all-yellow flowered species of columbine on the eastern slope of Colorado. This variety is endemic to El Paso and Fremont counties in Colorado. It is found in mountains, especially along streams or in rocky ravines, from 5500 to 6000 feet. The plant has bluish-green foliage (more)

 

*Arabis fecunda 

Arabis fecunda is a small perennial forb with clusters of basal leaves. Flowering stalks reach up to 12 inches in height and produce small white flowers during the month of May. This Montana endemic was first discovered in 1975 by Jaculyn Cory of Hamilton. It occurs on an unusual soil type in very (more)

 

*Arabis hoffmannii 

Less than 150 plants in 3 populations are known to exist. Two populations each have less than 5 reproductive plants annually. The remaining population may have as many as 30 reproductive individuals in any one year. Although reproductive plants produce many fruits and seeds, most of the seeds are (more)

 

*Arabis koehleri var. koehleri 

On a dry hill high above the rushing Umpqua River…precariously perched on a steep rocky outcrop …tucked into a small crack. That's where you will find the diminutive shrub, Arabis koehleri var. koehleri. Looking like something out of a Dr. Suess book, this tough, tufted member of the mustard (more)

 

*Arabis mcdonaldiana 

The small crimson to purple flowers of Arabis macdonaldiana are both beautiful and fragrant (Eastwood 1903). This interesting little plant was discovered in northern Mendocino County, California in 1902, and described as a distinct species the following year. Its discoverer was Alice Eastwood, (more)

 

*Arabis perstellata 

Arabis perstellata was named by E. L. Braun from plants collected between 1936 and 1939 on wooded hillsides along Elkhorn Creek in Franklin County, Kentucky. The plant is distinguished from other Arabis by the stellate (star-shaped) hairs on its stems and leaves. Braun's rockcress flowers from (more)

 

*Arabis serotina 

Shale Barren rock cress (Arabis serotina) is an erect flowering biennial or facultative biennial herb characterized by an inconspicuous basal rosette of lobed leaves. In its reproductive stage, the basal leaves shrivel as the slender stem grows, or "bolts", and the inflorescence develops. Mature (more)

 

*Arctomecon humilis 

This species of poppy is one of the rarest in the world, and was in fact one of the first species in the United States to be listed as federally endangered in 1979. Today, this species exists in only seven small locations outside of St. George, Utah, a city with a rapidly growing population. This (more)

 
*Arctostaphylos cruzensis 

 

*Arctostaphylos densiflora 

The Vine Hill manzanita is an extremely rare species that is endemic to Sonoma County, California. Three of the four historic occurrences of this species have been extirpated. In the 1990's the California Native Plants Society (CNPS) purchased the land where this last known population occurs and (more)

 

*Arctostaphylos glandulosa ssp. crassifolia 

The Del Mar manzanita is the rarest of the six recognized subspecies of Eastwood Manzanita, Arctostaphylos glandulosa. The Del Mar or Costa Baja manzanita, is a small to medium sized evergreen shrub with thick leathery leaves and clusters of dainty urn-shaped white to pink flowers in late winter to (more)

 

*Arctostaphylos hookeri ssp. franciscana 

The Franciscan manzanita was historically known to exist in three populations in San Francisco, two in cemeteries and one at Mt. Davidson. Unfortunately for the this plant, it was found on lands that were highly valued for commercial and residential property in the rapidly expanding city of San (more)

 

*Arctostaphylos hookeri var. ravenii 

Raven's manzanita is a low-growing evergreen shrub with urn-shaped white to pink flowers. It was rediscovered by Peter Raven when he was a young boy in San Francisco in 1952 (it was described as subspecies ravenii in 1968). There is one naturally occurring plant left in its native habitat, located (more)

 

*Arctostaphylos imbricata 

San Bruno Mountain manzanita is an attractive low-growing evergreen shrub with small white flowers. It is known from only five occurrences on San Bruno Mountain in San Mateo County, California. This manzanita is threatened by fungal infection, off-road vehicle activity, and possibly by alteration (more)

 

*Arenaria macradenia var. kuschei 

Arenaria macradenia var. kuschei is one of four recognized varieties of this species. This taxon was previously thought to occur in Inyo or San Bernardino County, and its habitat was previously reported as unknown in various treatments (Hickman 1993; Skinner and Pavlik 1994). Arenaria macradenia (more)

 

*Arenaria paludicola 

Once found in Pierce County, Washington and from San Francisco Bay to the San Bernardino Valley in California, marsh sandwort today is known from fewer than three localities, and its numbers have dwindled to perhaps less than perhaps 50 individuals. As early as 1915, marsh sandwort was considered (more)

 

*Argemone pleiacantha ssp. pinnatisecta 

The Sacramento prickle-poppy produces attractive, grapefruit-sized white flowers while spiny leaves and fruits protect the plant from many predators. This species is found along drainages and roadsides near the Sacramento Mountains in New Mexico. It is a robust, herbaceous perennial, with multiple (more)

 

*Artemisia porteri 

Viewed from a distance, Porter's sagebrush all but vanishes into the barren badlands, its silvery foliage practically invisible against the ash-gray backdrop. As if life isn't hard enough in the cold desert of central Wyoming, Porter's sagebrush grows in the harshest of habitats - the eroding clay (more)

 

*Asclepias meadii 

This rare, attractive species of Midwestern tallgrass prairies and glades. Today, all of the tallgrass prairie populations of this species in Wisconsin, Illinois, and Indiana have been destroyed by agriculture, and the only remaining native eastern populations occupy glade habitat in southeastern (more)

 

*Asclepias prostrata 

This rare, attractive species of Midwestern tallgrass prairies and glades. Today, all of the tallgrass prairie populations of this species in Wisconsin, Illinois, and Indiana have been destroyed by agriculture, and the only remaining native eastern populations occupy glade habitat in southeastern (more)

 

*Asclepias uncialis ssp. uncialis 

A small, herbaceous perennial with several to many stems 1 to 2.5 inches high. Stems have milky sap. Leaves are primarily opposite, and are of two different forms - lower leaves are oval to lanced shaped, while upper leaves are much narrower. Flowers have five reflexed petals with attendant hoods (more)

 

*Asclepias welshii 

Welsh's milkweed is an herbaceous perennial with extremely hairy and broad ovate leaves. Cream-colored flowers with rose-tinged centers are produced in a ball shaped cluster from May to June. Large seeds with rudimentary tufts of hairs develop and are dispersed from July to early September. (more)

 

*Asimina tetramera 

The four-petal pawpaw, Asimina tetramera, is an aromatic shrub or small tree in the Annonaceae family. Another species shares the common name of pawpaw with this plant, and that is the papaya (Carica papaya), a well known tropical fruit that is in the Cariaceae family. Asimina tetramera is (more)

 

*Asplenium heteroresiliens 

Asplenium heteroresliens is an evergreen perennial herb member of the Asplenium trichomanes group, with ovate pinnae, and the pinnae in the lower third of the frond somewhat descending and tending to form a low auricle on the posterior side of the base. (Jones-Roe 1982).

Carolina
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*Asplenium scolopendrium var. americanum 

Asplenium scolopendrium var. americanum, or American hart's tongue fern, is the North American variety of a European species that was described in 1753 by Linnaeus as Phyllitis scolopendrium. This variety was discovered in North America in 1849 in Tennessee, and since then has been found in (more)

 

*Asplenium verecundum 

Asplenium scolopendrium var. americanum, or American hart's tongue fern, is the North American variety of a European species that was described in 1753 by Linnaeus as Phyllitis scolopendrium. This variety was discovered in North America in 1849 in Tennessee, and since then has been found in (more)

 

*Aster furcatus 

Aster furcatus is a rare, self-incompatible plant that is endemic to the upper Midwest. This member of the Aster family is generally a woodland plant associated with low, wet areas. It has large white flowers that bloom from July to October, but that often fail to produce seed. Currently, this (more)

 

*Aster puniceus var. scabricaulis 

Correll and Johnston (1979) describe this rare plant found in boggy areas of Northeast Texas as a perennial with underground stems and weak above ground stems to 14-18 dm (55- 71 inches) long. The plants bear rough hairs throughout and have entire or shallowly toothed, sessile leaves. Ray flowers (more)

 

*Aster vialis 

Like so many other species, wayside aster is fighting an uphill battle to survive. To add insult to injury, it is not even a very attractive plant. Wayside aster lacks the showy, petal-like "ray flowers" that help many recognize other asters. This understated flower is threatened by habitat (more)

 

*Astragalus agnicidus 

Throughout history, humans have systematically eradicated plants and animals that seem to pose a threat to their livestock or crops. Bears, wolves, coyotes, and even condors have all been victims of ranchers' guns and traps. Astragalus agnicidus has fallen victim to the rancher's shovel and (more)

 

*Astragalus albens 

Astragalus albens is a small, silvery-white, low-growing perennial herb of the pea family. It is a member of an increasingly rare suite of 5 endemic plant species restricted to carbonate deposits in the San Bernardino Mountains of southern California. This attractive plant blooms March-May, (more)

 

*Astragalus ampullarioides 

Astragalus ampullarioides is an extremely rare species comprising four small populations in Washington County, Utah (Van Buren and Harper 2003). The species is restricted to Chinle soils and was Federally listed as Endangered in September 2001. Significant portions of this species habitat is (more)

 

*Astragalus anisus 

Colorado endemic in Gunnison and Saguache counties. Racemes of 3 to 7 flowers, pink-purple, corolla 15-20 mm long. Ovoid strigose pods, 15 to 20 mm in length. Dwarf plants, 5 to 10 cm in height. Leaves with 9 to 15 leaflets, each 4 to 10 mm in length, tomentose, and silvery.

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*Astragalus anserinus 

A. anserinus is a matt forming forb known to grow only on soils formed from ancient volcanic tuff. As one of the few species to populate these barren tuffaceaous outcrops, it assists with soil stabilization. In spring this plant will display bright pink - purple flowers on the backdrop of the (more)

 

*Astragalus applegatei 

In the mid-1980s, a significant portion of the largest remaining Applegate's milkvetch population was paved over to make way for an auto dealership and grocery store. Since the site, which was just outside Klamath Falls, Oregon, contained the largest remaining population, this destruction was (more)

 

*Astragalus australis var. olympicus 

Even though Astragalus australis var. olympicus is native only to high reaches in the Olympic Mountains of Washington, it is not immune to the impact that modern humans have had on the ecosystem. With an unfortunate lack of foresight, 12 mountain goats were introduced to the Olympic Mountains in (more)

 

*Astragalus barrii 

Springtime is fleeting in the Powder River country of eastern Wyoming and Montana, but at its peak it turns the tops of bluffs and buttes into rock gardens of remarkable beauty. An assortment of low-growing plants grace these windswept places, including Barr's milkvetch, a cushion-forming plant (more)

 

*Astragalus bibullatus 

Pyne's ground-plum is a beautiful legume that is endemic to the Central Basin of Tennessee. First described in 1987, the plant is found only in a cedar glade habitat (Barneby and Bridges 1987). The ground-plum gets its name from the fruits produced in late May to early June. While the lavender (more)

 

*Astragalus brauntonii 

This is an ephemeral perennial member of the pea family that reaches a height of 15 dm with dull lilac flowers blooming March-July (Munz 1974). It typically appears following a chaparral fire or other form of mechanical disturbance and persists several years before senescing or becoming crowded (more)

 

*Astragalus cremnophylax var. cremnophylax 

Sentry milk-vetch is a rock-hugging plant that literally grows in sites that overlook the Grand Canyon. It's scientific name means 'gorge watchman'. The population where this plant was first collected was threatened by trampling from the millions of visitors to Grand Canyon National Park. In (more)

 

*Astragalus debequaeus 

Plants are clump-forming perennials 2 to 10 decimeters (8 to 39 inches (in.) in diameter with a woody taproot; stems 14 to 30 centimeters (cm) (5.5 to 12 in.) long, curving upward; compound leaves 2 to 10 cm (0.8 to 4 in.) long with 13 to 21 glabrous, flat or somewhat folded leaflets. Flowers are (more)

 

*Astragalus desereticus 

Astragalus desereticus was considered extinct for 72 years prior to 1981 when it was re-discovered by Elizabeth Neese. One, small population exists in Utah County on highly accessible land that is used for cattle grazing and wildlife management (Franklin 1990). Astragalus desereticus is a (more)

 

*Astragalus deterior 

The Cliff Place milkvetch is an upright perennial and member of the Pea Family. It was first discovered in 1943 by Rupert Barneby, but considered a variety of Astragalus naturitensis for a few years until it was renamed by Barneby. This species is found close to some of the most spectacular (more)

 

*Astragalus detritalis 

Debris milkvetch is a perennial plant that is a member of the Pea family. It flowers from late April to early June, producing vivid pink-purple flowers. Its pinnately compound or trifoliate leaves have narrowly linear leaflets. Its pods are erect to straight or slightly curved, laterally (more)

 

*Astragalus equisolensis 

Astragalus equisolensis is a past federal candidate for listing. It is known from a limited range in Uintah County, Utah and from distan Mesa County, Colorado. It is a 5-15cm tall perennial with pink purple ascending or spreading flowers. It is strictly acaulescent or subacaulescent and branched. (more)

 

*Astragalus holmgreniorum 

Astragalus holmgreniorum (Holmgren’s Milkvetch) is a short-lived desert perennial. The first known collection of A. holmgreniorum occurred in 1941. It was discovered again in 1979 by Patricia and Noel Holmgren who, it was named for. In 1980 it was considered a candidate for federal listing it (more)

 

*Astragalus humillimus 

Mancos milkvetch is a diminutive, tufted perennial that is found in rock crevices. The leaves have spines along their central veins that remain after the leaflets fall. The plant flowers in late April and early May producing pale lavender to purple blooms. (ESIS 2002) Reaching for a closer look (more)

 

*Astragalus hypoxylus 

Plants are low herbaceous perennials, forming a rosette of branches that grow flat against the ground. The ends of the branches turn up a little, and the entire plant ranges from 10 cm in diameter in the wild, up to 30 cm wide in cultivation. Leaves are alternate, compound with 9-13 leaflets, and (more)

 

*Astragalus lentiginosus var. micans 

This clump forming perennial is actually on its way to becoming a success story. It was withdrawn from the Federal Threatened species list in 1998 once a recovery plan had determined the key threats to the species and the National Park Service acted on its suggestions and protected this species so (more)

 

*Astragalus linifolius 

Astragalus linifolius is a perennial plant that is a member of the legume family. It flowers from late May to June, producing hundreds of white flowers, each with a purple spot on their keel. This milkvetch produces bright red fruit pods in late June. The flower and fruit colors stand out all the (more)

 

 

*Astragalus microcymbus 

Astragalus microcymbus is a freely branching perennial with large, inflated pods and grayish foliage. Its name means 'little boat', which refers to the fruits that resemble an inverted skiff.

Its original discovery was very perplexing to Astragalus expert Dr. Barneby and University of
(more)

 

*Astragalus missouriensis var. humistratus 

Astragalus missouriensis var. humistrata is a perennial purple-flowered legume with pinnate basal leaves. Mature pods are necessary to distinguish this variety from related species A. amphioxys and A. chameleuce, as well as other varieties of A. missouriensis. Plants flower in May and set fruit in (more)

 

*Astragalus montii 

Astragalus montii is a low-growing alpine herbaceous perennial. Its tiny, pinnately compound leaves are dwarfed by comparatively large, inflated pinkish-brown seed pods. Two to eight pink-purple flowers with white wing-tips form at the end of stems during the months of June to August. (Geer & (more)

 

*Astragalus mulfordiae 

Mulford's milk vetch is in danger of being ignored out of existence. Like many other species not particularly attractive to the general public, Astragalus mulfordiae does not get the attention that it deserves. While this plant may not qualify beautiful by the average member of the public, does (more)

 

*Astragalus naturitensis 

A low, tuft-forming perennial herb, about 1 dm tall, growing from a basal rosette of leaves. Flowers (April-May) have white upper petals and red-purple lower petals. The plants are often only vegetative, and have extremely small pinnate leaves with tiny gray-green leaflets that tend to fold in (more)

 

*Astragalus osterhoutii 

Osterhout milkvetch grows in high-selenium soils. Selenium is concentrated in its plant tissue, producing an unpleasant odor (Dornbirer 1995). The plant is a tall, herbaceous perennial with rush-like stems. It produces numerous cream-colored flowers.
A significant part of the known range and
(more)

 

*Astragalus phoenix 

A. phoenix is a long lived, perennial forb that develops into low spreading mounds that can reach 15 cm high and 50 cm in diameter. Flowers are pink-purple and leaves are covered in dense, white hairs. This species grows in the highly saline soils of desert wetlands in eastern Nevada.
(more)

 

*Astragalus piscator 

A spreading, short-lived perennial herb, up to 3 dm wide. Bright pink-purple flowers bloom from late April-early June. (NatureServe). Plants have three to ten pink “pea type” flowers on leafless stems. Stems are erect when in flower, and often spread out at the base of the leaves when in fruit. The (more)

 

*Astragalus pycnostachyus var. lanosissimus 

Less than 50 plants are known to exist, represented by a single population. The population occurs on an abandoned oil-field waste site, which has been proposed for reclamation and development as a residential community. Historic records suggest that this variety occurred near coastal marshes or (more)

 

*Astragalus ripleyi 

Ripley’s milkvetch, a tall and robust perennial, is a member of the Pea Family. The type specimen was collected in 1950 near Tres Piedras, New Mexico by Rupert Barneby and named for his friend and collecting partner, H.D.D. Ripley. Later, William A. Weber found the taxon in Colorado where Francis (more)

 

*Astragalus robbinsii var. jesupii 

Astragalus robbinsii var. jesupii is an extremely rare member of the bean family, found only at three sites along a 15-mile stretch of the middle Connecticut River in New Hampshire and Vermont. This plant is found only in areas that receive periodic ice-scouring that clears competing vegetation (more)

 

*Astragalus schmolliae 

First collected by Alice Eastwood in 1890, this species grows only on the tops of mesas in a small part of Mesa Verde National Park. Schmoll's milkvetch produces yellowish-white to creamy colored flowers with black hairs on the calyx during the months of May and June. Seeds of this species have (more)

 

*Astragalus sinuatus 

Astragalus sinuatus is found only within a ten square mile (26 sq. km) area in Central Washington. Although much of the historic range of this species has been converted or destroyed by agriculture and grazing, there is quite a bit of suitable habitat remaining. Scientists do not know why A. (more)

 

 

*Astragalus tennesseensis 

This species is in the same genus as the plants referred to as 'locoweed', which are well known for their affect on cattle. Due to research by government organizations and universities, we now know a great deal about propagating this species from seed and cuttings (Native Plants Network 2002, (more)

 

*Astragalus tortipes 

Astragalus tortipes J.L. Anderson and J.M. Porter, the Sleeping Ute Milkvetch, is a very rare endemic plant known from 2 populations in southwestern Colorado. It is a relatively new species, described in 1994 by J.L. Anderson and J.M. Porter. It is distinguishable from other Astragalus species by (more)

 

*Astrophytum asterias 

small, spineless (more)

 

*Atriplex canescens var. gigantea 

Atriplex canescens var. gigantea, or giant four-wing saltbush, is a rare variety of a common species, Atriplex canescens, or four-wing saltbush. Giant four-wing saltbush grows at only one location in the wild--the Lynndyl Dunes in Juab County, Utah. The rare var. gigantea is considered a diploid (more)

 

*Atriplex pleiantha 

Mancos shadscale, an annual herb that is a member of Goosefoot Family was collected in southwestern Colorado and first described in 1950 by W. A. Weber. Now known from locations in northwestern New Mexico, southeastern Utah, and southwestern Colorado, it is most common on badland landscapes. The (more)

 

*Ayenia limitaris 

Ayenia limitaris is a 2-5 foot tall perennial herb/shrub with soft heart-shaped leaves. It belongs to the Sterculiaceae or Cacao family of plants. Cocoa and chocolate are derived from the seeds of the tropical American tree, Theobroma cacao L. (Correll and Johnston 1996).

Like many
(more)

 

*Banara vanderbiltii 

Banara vanderbiltii is a small evergreen shrub endemic to Puerto Rico. Adult plants have a rough, sandpaper-like textured leaves and bare, small, yellow hermaphroditic flowers that bloom from April through June and ripen into red/purplish fruits (Little et al. 1974). Two birds, the bananaquit (more)

 

*Baptisia arachnifera 

Perennial herb, 15 - 32 inches tall (40 - 80 cm), all parts covered with white, cobwebby hairs. Leaves ¾ - 2⅜ inches (2 - 6 cm) long and ½ - 2 inches (1.5 - 5 cm) wide, simple, alternate, oval to broadly heart-shaped. Flowers yellow, typical of pea flowers with an upright banner petal and 2 (more)

 

*Bartonia texana 

Slender, erect, glabrous annual to 30 cm tall. Leaves are alternate and reduced to scales (ca. 1 mm long). Flowers are in slender, lax racemes or panicles and very small (2.5 mm long) and (more)

 

*Basiphyllaea corallicola 

The Carter's orchid is a diminutive terrestrial orchid that is listed as endangered by the state of Florida. (more)

 

*Berberis nevinii 

Berberis nevinii is a large rounded shrubby member of the barberry family (Berberidaceae) that grows up to 4 meters tall, with blue-green, spiny pinnate leaves. This species is federally-listed as endangered and is also widely cultivated and popular in xeric gardens, in part for its bright red (more)

 

*Berberis pinnata ssp. insularis 

Although once known from three California Channel Islands, island barberry survives today at only 3 known localities on Santa Cruz Island, perhaps represented by only 1-3 plants in each. Intensive sheep and cattle grazing for over 150 years contributed to its loss on Santa Rosa Island. The last (more)

 

*Besseya bullii 

Besseya bullii is a short herbaceous plant that is easy to miss...until it blooms. For most of its life, this plant is in the form of a small rosette of hairy basal leaves that are two to five inches in length and have a tendency to hug the ground. However, from April until June this plant sends (more)

 

*Betula murrayana 

This species is an unusual natural hybrid of an already naturally hybridized species, purpus birch, Betula x purpusii, crossed with another native species, yellow birch, Betula allegheniensis. It can be described as a small tree or a tall shrub, ranging from 4-15m tall. The tree is 5-20cm in (more)

 

*Blennosperma bakeri 

The extirpation of Blennosperma bakeri from four of seven historic sites in the Sonoma Valley was caused by home construction and the planting of a vineyard. The remaining populations still face similar threats. However, both the local government and private citizens have begun to create artificial (more)

 

*Boechera pusilla 

A perennial herb with 2-several prostrate or gently arching stems up to 17 cm long, spreading outward from a basal rosette of leaves. Leaves have a sparse covering of soft-spreading hairs. Tiny, 4-petaled lavender flowers bloom in May and June, followed by narrow, smooth fruits that hang down at (more)

 

*Boltonia decurrens 

Endemic to Illinois and central eastern Missouri, Boltonia decurrens is one of the rarest native species in this region. In fact, until two Missouri Botanical Garden botanists rediscovered it north of St. Louis in 1986, the Decurrent false aster was thought to have been extirpated from (more)

 

*Bonamia grandiflora 

Bonamia grandiflora, the perennial scrub morning-glory, or Florida lady's nightcap as it is sometimes called, is the only species of its genus in the continental United States. If lucky, one will find this sprawling herb blooming from April through August with large, attractive deep blue or (more)

 

*Bonamia menziesii 

Bonamia menziesii is a member of the morning-glory family (Convolvulaceae). It is a vine or twining liana with branches that can measure up to 10 meters long. The leaves are usually leathery and oval shaped. Its flowers are white to greenish colored, funnel shaped and produced singly or in (more)

 

*Bonamia ovalifolia 

Bonamia ovalifolia is a very attractive herbaceous perennial growing from a woody crown. Stems are deciduous, dying back to the crowns in November, and re-emerging in April. Leaves are round, about 1 cm in diameter, and are silvery blue-green, on stems that reach 30-40 cm in height. Plants are (more)

 

*Brighamia insignis 

There are two threatened Brighamia species that are endemic to Hawai’i (U.S. Fish and Wildlife Service [USFWS] 2001). Current levels of wild seed production and regeneration are not thought to be sufficient enough to sustain wild populations. Poor seedling establishment due to competition with (more)

 

*Brighamia rockii 

There are two endangered Brighamia species endemic to Hawai’i (U.S. Fish and Wildlife Service [USFWS] 2001). One, Brighamia insignis, is found on the islands of Kauai and Niihau, and Brighamia rockii is found only on the island of Molokai. Both have succulent stems that act as a water storage (more)

 
*Brodiaea pallida 

 

*Brunfelsia densifolia 

Brunfelsia densifolia, commonly known as Serpentine hill rain tree, is a shrub known from only one area in Puerto Rico (Pence 1990). It is being successfully used as an ornamental shrub in South Florida. It is hardy in nature, requires little care, and produces beautiful tubular, yellow flowers (more)

 

*Buckleya distichophylla 

The American Buckleya, a rare shrub of the Santalaceae family, has a very limited distribution (Sutter et al. 1987). Trees and herbs in this family are usually found in the tropics and are often parasitic or semi-parasitic (Harper 1947). Buckleya distichophylla has dioecious flowers and is (more)

 

*Buxus vahlii 

Buxus vahlii grows on limestone formations in northern and northwestern semi-evergreen forests in Puerto Rico. Two remaining sites support about 40 individuals, none of which appear to be reproducing. (USFWS 1985, 1990)

Buxus vahlii is an evergreen shrub or small tree that can grow to a
(more)

 

*Caesalpinia kavaiensis 

There are four Caesalpinia species in Hawaii, three introduced and one endemic. Caesalpinia kavaiensis, or uhiuhi, was once fairly abundant on the islands of Hawaii, Oahu, Kauai, and Maui. The wood of C. kavaiensis is highly valued for its color, grain, and density. Hawaiians made spears with the (more)

 

*Caesalpinia phyllanthoides 

There are four Caesalpinia species in Hawaii, three introduced and one endemic. Caesalpinia kavaiensis, or uhiuhi, was once fairly abundant on the islands of Hawaii, Oahu, Kauai, and Maui. The wood of C. kavaiensis is highly valued for its color, grain, and density. Hawaiians made spears with the (more)

 

*Calamagrostis porteri ssp. insperata 

Calamagrostis insperata is a rare, cool season grass. This tufted perennial can stand up to 1 meter in height and is very attractive. Plants are very sensitive to habitat conditions and rarely flower in the wild. Even when they do flower, they rarely set viable seed, and this likely contributes (more)

 

*Calamintha ashei 

Calamintha asheii is an aromatic (member of the mint family), bushy shrub that can grow to two feet tall. Its up to 1/2 inch-long leaves are needle-like, and it produces small, pinkish-purple flowers from January to April. It is found mostly in openings of pine scrub habitat in Florida, but can (more)

 

*Calamintha dentata 

Calamintha dentata is an aromatic, bushy shrub that can grow to 5 decimeters tall. It grows a wide range of sandy, well drained habitats, such as pine sandhills, roadsides, and planted pine plantations. Plants are densely leaved, produce small purplish flowers, and have a minty odor. (NatureServe (more)

 

*Calamovilfa arcuata 

Calamovilfa arcuata is a flowering perennial grass that forms clumps between one to three feet wide. Although the plants grow along stream banks, too much water can be detrimental (Perkins and Patrick 1980). Several populations are thought to have been lost due to the construction of reservoirs (more)

 

*Callirhoe bushii 

Callirhoe bushii is a lovely member of the poppy family, producing striking magenta flowers. First described in 1909, the plant was named in honor of Benjamin Franklin Bush (1858-1937), a prominent botanist of the time. However, considerable debate ensued over the true taxonomic status of the (more)

 

*Callirhoe scabriuscula 

Texas Poppy Mallow is a perennial herb about 18 inches high with beautiful wine-purple, cup-shaped flowers. These flowers bloom from May to June, and a key source of nectar, pollen, and shelter for bees in the area. These bees help the plant reproduce by spreading pollen between plants. Each (more)

 

*Calochortus coxii 

When the crinite mariposa lily is not in bloom, it can be difficult to distinguish from grasses and is easily overlooked. Perhaps for this reason it was not discovered until the spring of 1988. However, this plant is akin to the ugly ducking that matures into a swan, as reproductive plants are (more)

 

*Calochortus dunnii 

This perennial plant has such a showy flower that the main threat to its existence is the humans who love it. People pick this flower without realizing that the plant is endangered. The flower is large and ranges in color from white to pink and has a red spot at the base of the petals. Collectors (more)

 

*Calochortus palmeri var. munzii 

Very little information is known about this species, although it appears to be relatively stable despite the fact that fewer than 2,000 plants remain in the wild. (Dudek & Associates Inc. (more)

 

*Calochortus umpquaensis 

As its name suggests, Calochortus umpquaensis is only found along the Umpqua River in southwestern Oregon. It is restricted to serpentine soils, which characteristically have high concentrations of heavy, toxic metals. Despite its narrow range and specific soil requirements, this rare lily occurs (more)

 

*Calycadenia villosa 

Dwarf Calycadenia is a summer-flowering annual up to 30 cm tall, with a basal rosette of many, grayish, simple leaves. Each plant can produce from 1 to 15 heads with 1-4 white to pinkish ray flowers and 10 to 15 disk flowers. Most populations are composed of plants with a single, simple to distally (more)

 

*Calyptranthes peduncularis 

This species is a shrub that grows from 1.5 to 2 meters tall. There is nearly no information in the literature about this species, other than the fact that it grows on serpentine barrens in Puerto Rico at altitudes of 300 to 400 meters. (New York Botanical Garden (more)

 

*Calyptranthes thomasiana 

Calyptranthes thomasiana is a small evergreen shrubby-tree that may reach up to ten meters in height (Vivali and Woodbury 1981, USFWS 1997). The species is currently known from three locations: the island of Vieques in Puerto Rico, St. John, the U.S. Virgin Islands and Virgin Gorda, British Virgin (more)

 

*Calyptronoma rivalis 

Calyptronoma rivalis grows along stream banks in the semi-evergreen forests of the karst region in Puerto Rico and can reach up to 12 meters in height (USFWS 1992). The palm has dioecious flowers that bloom twice a year and produce an abundant amount of small reddish fruits (Vivaldi and Woodbury (more)

 

*Campanula robinsiae 

The Brooksville Bellflower is an annual herb first found in the Chinesgut hill area of Hernando County, Florida in 1924. Campanula robinsiae was federally listed as endangered in 1989. Since that time, regular monitoring indicates that the number of plants within populations fluctuates greatly. (more)

 

*Canavalia molokaiensis 

Canavalia molokaiensis, member of the legume family (Fabaceae), is a short-lived, perennial climbing herb. It has twining branches with leaves made up of three lance (longer than wider)-shaped or sometimes oval leaflets (3.5 to 8 cm long, 1.3 to 5.4 cm wide) (USFWS 2000). The flowers have five (more)

 
*Cardamine longii 

 

*Cardamine micranthera 

This species was considered extinct for three decades, until its rediscovery in Stokes County, North Carolina in the mid-1980's. After this initial discovery, further searching led to the discovery of a total of 13 populations. The range of this species extends over two counties in the upper (more)

 

*Carex barrattii 

Barratt’s sedge is uncommon throughout most of it’s range. It is not federally protected under the Endangered Species Act, but is ranked as threatened or endangered in a number of states in which it is found.

One state where this species is doing well is New Jersey. In 1978 and 1979,
(more)

 

*Carex lutea 

Carex lutea is a rhizomatous, perennial sedge that grows in clumps with mostly basal leaves. It is distinguished from other Carex species by the bright golden yellow color of female spikes when the fruits mature, by how tall (up to one meter) and slender it is, and by its out-curved perigynia (more)

 

*Carex oronensis 

Carex oronensis is a sedge that grows in loose clumps up to a meter tall. It is endemic to a small area of Maine, and Maine's only known endemic plant species. Most of its 58 known populations contain few stems, with only a handful of populations encompassing more than fifty stems. Growing in (more)

 

*Carex roanensis 

After this sedge’s original discovery in 1936, it was not seen again until its rediscovery fifty years later. The original 1936 population has never been relocated. Due to the lack of information on this species, there is a great deal of debate over its taxonomic status. However, despite claims (more)

 

*Carex specuicola 

Navajo sedge is found in seep-springs on vertical cliffs of red-pink Navajo sandstone (Arizona Ecological Field Services Office 2002). At first glance, this perennial sedge looks a lot like a grass, with 25-40 cm long, grass-like leaves growing in bunches. However, this plant is a sedge, not a (more)

 

*Castanea pumila var. ozarkensis 

The glory days of the Ozark chinquapin are past. Like the famous American chestnut of the Appalachian Mountains, Ozark chinquapin was decimated by the chestnut blight that was accidentally introduced into North America in the early part of the last century. Today, survivors of the blight hang on as (more)

 

*Castilleja aquariensis 

Astragalus aquariensis is a perennial herb 6-12in. tall with spikes of vibrant yellow flowers that bloom late June-August. It is endemic to Utah and likely somewhat parasitic.

As of 2006 this species was no longer listed as a candidate because a recent survey found more individuals than
(more)

 

*Castilleja christii 

Castilleja christii is one of Idaho's rarest plants--it is found in a single population in the Albion Mountains of Cassia County, Idaho. It was named after John H. Christ, the first botanist to collect this species. This showy perennial herb grows from 6 to 8 inches tall and produces yellow to (more)

 

*Castilleja elongata 

The Chisos paintbrush is known only from the Chisos Mountains in Big Bend National Park, Texas (USFWS 1998). It is reportedly hemiparisitic, obtaining water and nutrients from host plants by forming haustorial connections with the roots of nearby grasses and other plants (Heckard 1962, Mills and (more)

 

*Castilleja gleasonii 

This perennial hemiparasite (root parasite) is an endemic to the San Gabriel Mountains, with a limited range in the western part of the mountain range in the Mount Gleason area. Its scarlet inflorescence is showy like many other related paintbrushes, blooming from April to July, however this taxon (more)

 

*Castilleja grisea 

Plants in the genus Castilleja are generally referred to as paintbrushes, with vibrant flowers resembling paintbrushes themselves, these plants are often considered among the most beautiful of the United States' wildflowers. The San Clemente Island paintbrush is endemic to the Channel Island of (more)

 

*Castilleja kaibabensis 

Kaibab Indian paintbrush is one of fourteen species of Castilleja that is found in Arizona (Lehr 1978). This particular species is a woody herbaceous perennial. Its hairy, lance-shaped leaves arise along hairy stems that grow to approximately 40 cm tall. Bracts are also hairy and flowers vary (more)

 

*Castilleja levisecta 

The bright, warm colored bracts that enclose Indian paintbrush flowers capture the attention of pollinators and hikers alike. Golden paintbrush is no exception. Of the 42 paintbrush species in the Pacific Northwest, this is the only yellow-bracted one in its range (Eastman 1990). Populations of (more)

 

*Castilleja salsuginosa 

Castilleja salsuginosa is a Nevada endemic and occurs in extremely fragile habitats. This herbaceous perennial is approximately 1.8 dm tall. The entire plant appears purplish to brown, on some occasions it may appear gray. The inflorescence is marked with cream and pink colored bracts and (more)

 
*Ceanothus impressus var. nipomensis 

 

*Ceanothus ophiochilus 

This species was only recently discovered in 1989. This member of the buckthorn family has small, thick, narrow leaves and blue of lavender flowers. It is only found on 20 acres near Vail Lake in Riverside County, California and it grows near an ancient volcano cone on soil rich in pyroxenite. This (more)

 

*Centaurium namophilum 

Centaurium namophilum is a perennial herb that flowers late spring to early fall. It is listed federally as a threatened species. It is an endemic species found on alkaline soils of wet saltgrass meadows, springs, and seeps that are restricted to Ash Meadows National Wildlife Refuge. The species (more)

 

 

*Cerastium arvense var. villosissimum 

We know almost nothing about this rare variety of Cerastium arvense, or prairie chickweed. Kartesz (1999) recognizes five subspecies of Cerastium arvense, and between them all they are located in nearly every state in the United States, including Alaska, as well as nearly every province in (more)

 

*Cercocarpus traskiae 

The Catalina Island mountain mahogany is considered to be one of the rarest shrubs in the continental United States. It has been rare as long as its existence has been known. This tree was first discovered in 1897 when there was a single population of forty individuals. Now there are only seven (more)

 

*Cereus eriophorus var. fragrans 

Harrisia fragrans is a columnar cactus endemic to south Florida. It may reach 3-5 m tall (reports vary), though it frequently has a sprawling, more horizontal growth form (Britton and Rose 1920, Benson 1982, USFWS 1988). The fragrant, showy, pink to white flowers reach 10 cm long and bloom (more)

 

*Chamaesyce celastroides var. kaenana 

Chamaesyce celastroides is by far the most variable and widespread of all Hawaiian Chamaesyce and is separated into 8 varieties (Wagner et al. 1999). One of the varieties of Chamaesyce celestroides is kaenana, which is a rare and endangered beach plant from O`ahu. It grows as a shrub or small (more)

 

*Chamaesyce deltoidea ssp. deltoidea 

Chamaesyce deltoidea ssp. deltoidea is a federally endangered, prostrate, perennial herb with wiry stems and tiny wedge-shaped leaves. It is found only in the extremely rare pine rockland ecosystem of Miami-Dade County, and occurs in mats over exposed limestone (DERM 1993, 1996). These (more)

 

*Chamaesyce skottsbergii var. kalaeloana 

Perennial, erect shrub with spindly, segmented, brittle branches and small, opposing ovate to orbicular leaves. Specimens range to 2 meters in height, but most are 0.5 to 1 meter tall. Plants are summer deciduous in their natural habitat, but retain leaves with irrigation. Copious milky white sap. (more)

 

*Chamaesyce skottsbergii var. vaccinioides 

Perennial, erect shrub with spindly, segmented, brittle branches and small, opposing ovate to orbicular leaves. Specimens range to 2 meters in height, but most are 0.5 to 1 meter tall. Plants are summer deciduous in their natural habitat, but retain leaves with irrigation. Copious milky white sap. (more)

 

*Chionanthus pygmaeus 

The Pygmy fringe tree is an endemic shrub native to the coarse, wind-deposited sands of central Florida. It is long-lived, and can persist in areas that are burned once every 20 to 70 years. This species depends on fire to maintain the open, sandy patches it requires. This fringetree has (more)

 

*Chloris texensis 

Texas windmill-grass is a tufted perennial with blue-green leaves that can reach knee high, but usually is much shorter than this. Plants often bear stolons or underground stems. Each flower shoot supports a whorl of five to ten spikes per panicle, five to eight-inches long, which radiate from the (more)

 

*Chlorogalum purpureum var. purpureum 

Purple amole is a bulbous perennial with 3-7 basal spreading leaves. Each plant produces a central naked inflorescence 25-50 cm tall, which bears 7-30 flowers. Purple amole has a fragmented distribution with less than 500 documented sites or "populations" distributed within 4-5 disjunct areas. (more)

 

*Chlorogalum purpureum var. reductum 

Camatta Canyon amole is a bulbous perennial with 3-7 basal, spreading leaves, 1-5 ascending inflorescences 10 - 20 cm tall, and flowers with 6 bluish purple sepals and petals. This variety is known from only 2 sites, separated by over 5 km. Most of the plants occur in one area of about 2-3 (more)

 

*Chrysopsis floridana 

Chrysopsis floridana, or Florida golden aster, is a perennial herb that is wooly from the basal rosettes all the way to the top of the stem. The leaves at the woody base are 4 to 10 cm long, 1.5 to 2.0 cm wide, and they are densely short-wooly pubescent. The leaves on the stems are about the same (more)

 

*Chrysosplenium iowense 

If you were to travel back in time to the last ice ages, about 15,000 years ago, you would likely see a land covered by glaciers, with the exception of a small area in Minnesota, Iowa, Wisconsin & Illinois. This area would appear to you as an island full of plant and animal life surrounded by a (more)

 

*Chrysothamnus molestus 

C. molestus is a perennial prostrate shrub or sub-shrub that is found only on the Coconino Plateau in northern Arizona. It produces profuse yellow rayless flowers in the fall and can be distinguished from common rabbitbrush by its hairy leaves which are less than 2mm wide. (Cobb et al. 1996) Cobb (more)

 

*Cimicifuga arizonica 

Arizona bugbane is an herbaceous perennial that reaches 3-6 feet in height. It has large, long-petioled lower leaves and small sessile upper leaves. The toothed leaf blades are divided into three leaflets. This species produces rather showy white flowers that grow on long stalks and bloom in (more)

 

*Cirsium aridum 

Thistles are more often thought of as weeds than plants in need of conservation, but the Cedar Rim thistle is one of a handful with very limited distributions. Known only known from the cold desert country of central Wyoming, Cedar Rim thistle grows on barren hills and slopes where its silvery, (more)

 

*Cirsium barnebyi 

Cirsium barnebyi is commonly called Barneby’s thistle. This plant is endemic to the Uintah Basin. It is a small headed flower plant of the Green River shale outcrops. This perennial emerges from a taproot. The flower is a bluish to pink/purple color (Welsh, 2003). (more)

 

*Cirsium hillii 

Cirsium barnebyi is commonly called Barneby’s thistle. This plant is endemic to the Uintah Basin. It is a small headed flower plant of the Green River shale outcrops. This perennial emerges from a taproot. The flower is a bluish to pink/purple color (Welsh, 2003). (more)

 

*Cirsium ownbeyi 

Ownbey's thistle is the rarest native thistle in Colorado. First discovered in the state in 1987, it is found in the dry canyons and cliff walls of northwestern Colorado and northeastern Utah. Current research is attempting to determine the effect of an introduced biocontrol agent (Rhinocyllus (more)

 

*Cirsium perplexans 

A native thistle, endemic to Colorado. Cirsium perplexans is an erect perennial or biennial, 2 to 6 dm tall. Stems are often purplish and slightly tomentose. Leaves are toothed with short weak spines, glabrate above, and tomentose below. Upper leaves are clasping at the base. Flowers are purple to (more)

 

*Cirsium pitcheri 

This herbaceous plant grows for 5-8 years before flowering. It blooms and sets seed once in its life. It stays open from June until September, and is visited by up to 30 different insect species. When it flowers, it has one stem, and many branches. The entire plant can be up to 3 feet tall. The (more)

 

*Cirsium vinaceum 

Cirsium vinaceum is a perennial thistle, 1-2 m tall, with a scapose rosette of spathulate, sessile, spiny-edged leaves (30-40 cm long) from which tall, branched inflorescences arise. The purple flowers are clustered in heads borne on nodding pedicels at ends of branches. The heads are relatively (more)

 

*Clarkia franciscana 

Presidio clarkia is a slender annual herb, less than 0.4 m. tall with lavender-pink flowers that open from May to July. It is restricted to serpentine substrates in the San Francisco Bay area of California, where it is currently known from fewer than 5 sites in San Francisco and Alameda counties. (more)

 

*Clarkia imbricata 

Vine Hill clarkia is a late-blooming, slender annual herb with large white or pinkish flowers. This species grows in habitats with sandy loam soils. Historically, it is known from only two natural occurrences in the Vine Hill area of Sonoma County, California. One of these is extirpated, leaving a (more)

 

*Claytonia lanceolata var. peirsonii 

Claytonia lanceolata var. peirsonii is an endemic to the eastern end of the San Gabriel Mountains of the Western Transverse Ranges. This perennial herb grows at high elevations from a globose corm generally with 2 cauline, reddish-green leaves that emerge right after snow melts (Mistretta and (more)

 
*Claytonia ozarkensis 

 

*Claytonia virginica var. hammondiae 

The plants grow in clumps at the edge of and also in spring fed acidic water seepages along the lower southeast flank of the Kittatiny Mountains in Northwestern New Jersey. The plants are morphologically indistinguishable from Claytonia virginica, except for petal and anther color. Typical plants (more)

 
*Clematis addisonii 

 

*Clematis hirsutissima var. arizonica 

This taxon's standing as a true variety has been called into question, and a morphological study showed that there was no clear difference between this variety (var. arizonica) and the more common variety (var. hirsutissima). (Pringle 1997) However, the U.S. Forest Service lists it as a sensitive (more)

 

*Clematis socialis 

Alabama leather flower is an erect, non-viney perennial herb known from only five sites in northeast Alabama and one in northwest Georgia (USFWS 1989; NatureServe 2001). It was first discovered in St. Clair county Alabama in 1980 (USFWS 1989). It is found in silt-clay alluvial soils in full sun (more)

 

*Clematis viticaulis 

Clematis viticaulis is an herbaceous perennial in the buttercup family (Ranunculaceae). Branches are laden with leathery green, deciduous leaves. These leaves overtop the central axis, a way to differentiate this species from a closely related species (Keener 1967). Greenish flowers on long (more)

 

*Cleome multicaulis 

Cleome multicaulis, the slender spiderflower, is an erect annual herb, with unbranched or sparingly-branched stems in the Caper Family. Its leaves are divided into three narrow leaflets, often folded along the midrib. It flowers from June to August, producing four small, delicate, pinkish-purple (more)

 

*Clermontia pyrularia 

Named for the pear shape of their fruit, there are likely less than five trees of Clermontia pyrularia left in the wild. These trees are only found on the island of Hawai'i on the facing slopes of two neighboring mountains. The few remaining plants are in extreme danger due to their low numbers and (more)

 

*Collinsonia verticillata 

Collinsonia verticillata is a woodland herb that grows from a hard, thickened rhizome. It produces flowers that range in color from white to pink and lavender in May and April. It produces fruit in June and July. There are 2-3 pairs of leaves, and unbranched inflorescence. It flowers with 4 (more)

 

*Colubrina oppositifolia 

There is just one endangered Colubrina species that is endemic to Hawai’i (U.S. Fish and Wildlife Service [USFWS] 2001). C. oppositifolia has one of the hardest native woods and took the place of metals in the economy of ancient Hawaiians. It was used to make kapa (cloth) beaters, poles, spears (more)

 

*Conradina brevifolia 

Short-leaved rosemary is one of five shrubby mints found in central Florida scrub habitat. This species is a short-lived, aromatic, perennial shrub that grows to 1 m in height. It has highly branched stems and leaves that are linear, 4-8 mm long, and fleshy. The larger leaves on well-developed (more)

 

*Conradina etonia 

Conradina species are aromatic shrubs with small narrow leaves, similar to the herb rosemary (Rosmarinus officinalis). Etonia rosemary (Conradina etonia) is a short-lived woody perennial, with mature plants living several years before declining. This species flowers in the summer, producing (more)

 

*Conradina glabra 

This rare mint, the Apalachicola rosemary, was listed as federally endangered in 1993. At that time, there were seven known locations of this species, six of which were on private timber company land. Since that time, the one population on State land has disappeared, but The Nature Conservancy (more)

 

*Conradina grandiflora 

This pungently, essentially evergreen, aromatic shrub is in the mint family. There are 5 species in this genus that are found in the southeastern United States, and all but 1 are considered rare or endemic. This particular species, Conradina grandiflora, is particularly memorable because, as its (more)

 

*Conradina verticillata 

While this species may closely resemble common rosemary to many people, it is an old species native to the southeastern United States. It is increasingly endanger of damage from nature lovers unintentionally causing damage to the few remaining populations. Several populations are located in Big (more)

 

*Consolea corallicola 

Opuntia corallicola is a prickly pear cactus endemic to the Florida Keys. Plants can grow to a tree-like form, with a trunk differentiated from the branching upper cladodes (Britton and Rose 1920, Small 1930) (the common name, "semaphore cactus," refers to the species' resemblance to the posts (more)

 

*Cordia rupicola 

This species is found in Puerto Rico and the British Virgin Islands. For a number of years it was considered extinct, until one small population was found on Puerto Rico and another was subsequently found on the island of Anegada in the Virgin Islands (KEW Scientist 2000).

Cordia
(more)

 

*Cordylanthus maritimus ssp. maritimus 

Unlike the other annual plants of the coastal salt marsh, Cordylanthus maritimus ssp. maritimus is a hemiparasite. This is an uncommon feature in southern California salt marshes and makes this plant truly unique. It's purple stems and bright white flowers provide color to the salt marsh long after (more)

 

*Cordylanthus maritimus ssp. palustris 

The Point Reyes bird's-beak (Codylanthus maritimus ssp. palustris) is only found on the coastal beaches of northern California and Oregon. It was once found from Morro Bay, San Luis Obispo County, California (about 200 miles south of San Francisco) to as far north as Tillamook County, Oregon. It (more)

 

*Cordylanthus palmatus 

The Point Reyes bird's-beak (Codylanthus maritimus ssp. palustris) is only found on the coastal beaches of northern California and Oregon. It was once found from Morro Bay, San Luis Obispo County, California (about 200 miles south of San Francisco) to as far north as Tillamook County, Oregon. It (more)

 

*Corema conradii 

Named after its discoverer, S. White Conrad (1779-1831), Corema conradii is one of the rarest plants in Massachusetts. It is a low, densely branched evergreen dioecious shrub with heath-like leaves and purplish flowers (Brown 1913, Norton 1913, Campbell and Hyland 1975). It belongs to a small (more)

 

*Coreopsis latifolia 

Broad-leaved tickseed is a slender, erect, perennial herb that grows in rich sandy-loams of the Blue Ridge Mountains. It is found in and around the Black Mountains and along the Blue Ridge Escarpment from the Craggies to the South Carolina line with disjunct populations in Tennessee (Sutter (more)

 

*Corispermum navicula 

Corispermum navicula Mosyakin, the boat-shaped or crescent bugseed, is a recently described (1995) species from Colorado with few localities and individuals. It is a 5-15 cm tall annual with broad, narrowly lanceolate or linear-lanceolate leaves. It flowers in late summer to fall.
(more)

 

*Cornutia obovata 

Cornutia obovata, an evergreen tree that can reach 30 meters in height, grows in the limestone hills and lower montane forests of northwestern and central Puerto Rico (USFWS 1987). Its purplish flowers grow in clusters at the end of branch stems.

Only seven individuals are known to
(more)

 
*Coryphantha albicolumnaria 

 

*Coryphantha minima 

The Nellie Cory Cactus, Coryphantha minima, was listed as endangered on November 7, 1979. The plants are small, round, up to 2.5 cm tall, and 1.2 cm in diameter, densely spied with yellowish spines. Flowers are rose-purple, and up to 1.cm tall, in May. Fruits are green and fleshy when (more)

 

*Coryphantha ramillosa 

C. ramillosa is a small, multiheaded cactus with slender spines that curve in all directions. Flowers are pale pink to deep rose, and fruits are green and juicy at maturity. It was officially listed as threatened by the U.S. Fish and Wildlife Service in November 1979.

Five new sites
(more)

 

*Coryphantha recurvata 

C. ramillosa is a small, multiheaded cactus with slender spines that curve in all directions. Flowers are pale pink to deep rose, and fruits are green and juicy at maturity. It was officially listed as threatened by the U.S. Fish and Wildlife Service in November 1979.

Five new sites
(more)

 

*Coryphantha robbinsorum 

Small (1.0-1.5 cm) above ground, unbranched cactus, 1.4-6.0 cm wide. This diminutive globular cactus is covered with tiny, grooved tubercules (Hunt 1978). Each tubercule has an areole filled with long white trichomes, and 11-17 radial spines (Earle 1963). A deep furrow can be seen on the upper (more)

 

*Coryphantha scheeri var. robustispina 

Coryphantha scheeri v. robustispina is a small globular cactus that reaches 10-18 cm in height with distinctive, straw-colored central spines (ca 2 cm long on mature plants). Plants have prominent tubercules, the tip of each having an aeroele. Young aereoles are densely covered with wool, old (more)

 
*Coryphantha sneedii var. leei 

 
*Coryphantha sneedii var. sneedii 

 

*Crataegus harbisonii 

The Harbison hawthorn is one of the rarest woody plants in the United States. After many years of research into its history, distribution, and taxonomy, several points have been made clear. The entity is distinct from other hawthorns, being closely related only to two other species in the genus. (more)

 

*Crescentia portoricensis 

Crescentia portoricensis is an evergreen, vine-like shrub that grows along stream banks in the Commonwealth Forests of southwestern Puerto Rico. This species can reach up to 6 meters in height and produces hermaphroditic, yellowish-white bell shaped flowers that ripen into dark green fruits (Little (more)

 

*Crotalaria avonensis 

This spreading, perennial herb was named in 1989 and listed as endangered in 1993. It is a bushy plant that hugs the ground with clusters of fuzzy, grayish leaves and short stems bearing small yellow flowers at the tips. Each plant can have one to three rather hairy, flowering stems that will (more)

 

*Croton alabamensis var. texensis 

A surprisingly conspicuous semi-evergreen shrub, Texabama croton escaped detection until 1989, when it was almost simultaneously discovered at Fort Hood and on the Balcones Canyonlands NWR. Readily recognized by foliage alone throughout the growing season, particularly in autumn when that foliage (more)

 

*Cryptantha barnebyi 

Cryptantha barnebyi is endemic to the Uintah Basin. This perennial is a long lived hardy plant; over thirty years ago a field researcher tagged these plants for monitoring purposes. The tags have remained where they were originally placed, it has been reported that the majority of the plants (more)

 

*Cryptantha crassipes 

Cryptantha crassipes, a long-lived herbaceous perennial in the Borage family, is an unusual clump-forming plant with leaves that are covered with silvery-gray hairs. Clumps develop gradually, beginning as seedlings, then forming a new ring of leaf-clusters each growing season. A black sooty (more)

 

*Cryptantha grahamii 

Cryptantha grahamii is a long lived perennial of the Uintah Basin. The plant arises from a thick taproot. The plant is from 15 to 25 cm tall. The flowers are white; several flowers are spread throughout the raceme. The number of stems per a plant varies. Plants are covered with hundreds of fine (more)

 

*Cryptantha subcapitata 

The foothills of Wyoming's Owl Creek and Bridger mountains are dry, desolate jumbles of rock and clay, yet the Owl Creek miner's candle occurs nowhere else, part of the tapestry of dwarf plants that mantles the rocky ridges and slopes. When not in bloom, it is hard to distinguish this plant from (more)

 

*Cucurbita okeechobeensis ssp. okeechobeensis 

Cucurbita okeechobeensis ssp. okeechobeensis (Okeechobee Gourd) is a wetland gourd, growing fairly commonly as a vine in the bottomlands of the St. John's River and the southern shore of Lake Okeechobee. It grew and reproduced in perfect synch with the natural hydrologic cycle of its habitat. (more)

 

*Cuphea aspera 

Cuphea aspera is a perennial herb that produces flowering stems that are 8-16 inches tall. On these stems, small pinkish purple flowers appear from June - July. Leaves are rough and hairy, lance or oval shaped, with entire margins. The common name (waxweed) comes from the waxy or sticky feel of (more)

 

*Cupressus abramsiana 

Santa Cruz cypress is an erect, densely branched, compact, coniferous tree with slender branchlets and cones containing six to eight seeds per scale. It grows on old marine sandstones or granitic soils in chaparral and closed-cone pine forest communities. This cypress is restricted to a localized (more)

 

*Cyanea asarifolia 

Discovered fairly recently in 1970, Cyanea asarifolia was known only from a single population of five or six plants above the bed of Anahola Stream on the island of Kaua`i. Recent attempts to relocate this population have failed and this population is now thought to be extinct. In 1991, another (more)

 

*Cyanea crispa 

Cyanea crispa is only known from O`ahu's Ko`olau Mountain Range in diverse habitats ranging from steep, open mesic forests to gentle slopes, to moist gullies of closed wet forests. Currently there are only 5 populations remaining consisting of 30-50 individuals. Three of these populations have (more)

 

*Cyanea grimesiana ssp. obatae 

Cyanea grimesiana ssp. obate was collected in 1965 by John K. Obata, but not named until 1978 by Harold St. John. When the species was listed as Federally Endangered in 1994, all known populations (totaling only 18 plants at most) were located on privately owned land. (USFWS 1994)

This
(more)

 

*Cyanea lanceolata ssp. lanceolata 

Cyanea lanceolata subspecies lanceolata is a small woody shrub found only on the island of O`ahu in the Ko`olau Mountain Range. It was once a relatively common understory shrub in mesic and wet forests, but has become increasingly harder to find. Currently, there are less than 300 plants left in (more)

 
*Cyanea leptostegia 

 

*Cyanea pinnatifida 

Cyanea pinnatifida was first collected by Chamisso, the botanist on the Russian exploring expedition which visited Hawai`i in 1816-1817. It grows in the Wai`anae Mountains on the island of O`ahu and has apparently been a rare species for a very long time, as only a few collections have been ever (more)

 

*Cyanea superba ssp. superba 

Cyanea superba is a palm-like tree sometimes reaching 20 feet in height that is crowned by a tight rosette of leaves. It bears numerous white and cream-colored flowers on pendant inflorescences that hang up to a foot below its leaves. This species is most severely threatened by habitat (more)

 

*Cycladenia jonesii 

This federally threatened species is threatened by off-road vehicle activity, as well as the presence of mining claims and oil and gas leases on or adjacent to known locations of this plant. (State of Utah Natural Resources 2002)

Jones' cycladenia is a long-lived perennial herb that
(more)

 

*Cyperus grayoides 

This sedge is fairly abundant in the few locations where it occurs. It requires open and deep sand dunes that are regularly disturbed by a variety of factors. While development has clearly hurt this population, as has fire suppression, the impact of grazing depends a great deal on the animal doing (more)

 

*Cypripedium kentuckiense 

The Southern lady’s slipper orchid is a tall, stately perennial herb with the largest flowers of any Lady’s slipper (i.e., Cypripedium) known. Once seen in flower it is never forgotten.

The stems are erect, 3.5-9.7 dm tall with 2-9 alternate ovate to ovate lanceolate leaves to 15 cm
(more)

 

*Dalea carthagenensis var. floridana 

Florida prairie-clover is a suffrutescent (having a stem that is woody only at the base; somewhat shrubby) shrub 3-6 feet (0.5-2.0 meters [m]) tall (Bradley and Gann 1999, p. 42; Chafin 2000, NA). Bradley and Gann (1999, p. 42) described it as follows: Leaflets 15-23, ovate to elliptic, 5-14 mm (more)

 

*Dalea cylindriceps 

Dalea cylindriceps is a short-lived perennial herb in the Bean Family (Fabaceae). It grows 3-6 cm tall and has pinnate leaves with 7-9 leaflets. Its most distinctive trait as a member of the genus Dalea is the length and thickness of the flower spike, which can reach up to 18 cm in length. It (more)

 

*Dalea foliosa 

Dalea foliosa is a perennial in the legume family (Fabaceae) that produces dense clusters of small purple flowers in early August. Leafy prairie-clover was first observed and documented in the late 1850's. Since then, known occurrences of the species have declined dramatically due to habitat (more)

 

*Dalea reverchonii 

Comanche Peak prairie-clover is a low, spreading perennial, which appears as a dense, mat-forming rosette up to 16 inches in diameter. Numerous thick, 3 inch long spikes of rose-pink to magenta-purple flowers bloom in May, before other Dalea species, and continue through June. The smooth, (more)

 

*Dalea tentaculoides 

Dalea tentaculoides is a shrub with numerous stems. The compound leaves have 9-17 leaflets, and the small, pea-like flowers are rose-purple in color. The plant flowers in April, through June, and sometimes again in September-October. It is very similar in appearance to at least three other Daleas (more)

 

*Deeringothamnus pulchellus 

The small size of this species makes it easy to miss in its native habitat. It is a low-growing, deciduous, aromatic shrub or subshrub rarely grows more than 30 cm (0.5 meters) tall. One to several erect (if in mowed habitat) or arching (if in burned habitat) stems ascend from a taproot. These (more)

 

*Deeringothamnus rugelii 

This species is a low, deciduous woody shrub or subshrub that grows to 50 cm tall. The species has 1 to several arching stems that arise from a taproot. The alternate, leathery leaves are oblong, to oval or obovate from 1 to 7 cm long. This species is very small and easy to miss. Flowers are lemon (more)

 

 

*Delissea rhytidosperma 

The genus Delissea is among the most threatened of Hawaii’s endemic genera. There are ten recorded species, of which only four have survived (U.S. Fish and Wildlife Service [USFWS] 2001).

D. rhytidosperma, a member of the bellflower family (Campanulaceae) is a branched shrub 0.5 to 2.5
(more)

 

*Delissea undulata ssp. undulata 

Delissea undulata subspecies undulata is an unusual palm-like tree that was observed in the late nineteenth century on western Hawaii in North and South Kona. It was last found in South Kona at Pu`u Lehua in 1971, but was later thought to be extinct. In 1992, a single adult individual was (more)

 

*Delphinium bakeri 

Baker’s larkspur remains as a single small population along a roadside in Marin County, California, not far from the Pacific coast. This perennial herb grows erect to 45 cm. tall; and features blue flowers in the spring. It was formerly more common in the coastal area, north into Sonoma County, but (more)

 

*Delphinium hesperium ssp. cuyamacae 

The Cuyamaca larkspur is an herbaceous perennial in the buttercup family, and has leafy stems that bear dense blue-violet blooms. This species is found in two counties in California, and appears to be stable in the wild, due in large part to the establishment of the Cuyamaca Meadows Natural (more)

 

*Delphinium leucophaeum 

Delphinium is a large, circumboreal genus of herbaceous perennial taxa many of which are widely distributed. The vast majority of species have blue, bumblebee pollinated flowers. Ken Chambers, a dean of Oregon botany, noted a surprising coincidence in there being three rare larkspurs in the (more)

 

*Delphinium luteum 

The picturesque coast of California north of San Francisco is the only home for the yellow larkspur. Now found in only two locations, both on private land, it was probably never widely distributed, occurring on rocky areas within coastal scrub at elevations up to 100 meters. Loss of habitat due (more)

 

*Delphinium pavonaceum 

Between 13,000 and 15,000 years ago, a series of huge ice dams formed in Montana, backing up very large lakes. The dams occasionally broke unleashing immense amounts of water that tore through Oregon and Washington at tremendous speeds (nearing 90 miles per hour (144 kph)). The resulting Missoula (more)

 

*Delphinium variegatum ssp. kinkiense 

The San Clemente Island larkspur (Delphinium variegatum ssp. kinkiense) is one of 13 plant species that are only found on San Clemente Island. Of the island’s 272 native plant species, 47 of them, or 13% of the islands total flora, occur only on one or more of the Channel Islands and no where else (more)

 

*Delphinium variegatum ssp. thornei 

Three varieties of Delphinium variegatum are known. One, D. var. variegatum, is found along the coast and foothills of central and northern California. Another is the Federally Endangered D. var. kinkiense, or San Clemente Island larkspur, which is endemic to (found only on) San Clemente Island, (more)

 

*Delphinium viridescens 

This unusual looking delphinium is tall (3-6 ft or 1-2 m), and has a narrow stalk of 30 to 50 closely spaced greenish-brown flowers. Most delphiniums are blue, purple, or red and attractive to animals (i.e. Hummingbirds) and bumblebees. Delphinium viridescens attracts only bumblebees. (more)

 

*Descurainia torulosa 

Descurainia torulosa is a small multi-stemmed biennial or short lived perennial in the mustard family. Tiny yellow flowers grow from the stems' tips and bloom in June. In late July the plant produces linear, hairy fruits, 8-15 mm long. (Atwood 1994).

The tansy mustard does not seem to
(more)

 

*Desmodium humifusum 

Desmodium humifusum is a prostrate, trailing, perennial herb in the pea family. It is found in dry, sandy, inland forests, ranging from Massachusetts south to Pennsylvania and west to Indiana. Once known from 35 herbarium collections from 19 sites in the northeast, the number of populations has (more)

 

*Dicerandra christmanii 

Dicerandra christmanii is a small fragrant shrub smelling of eucalyptus. It reaches a height of up to 1.3 feet tall. The stems are square with low ridges. Both stems and leaves, which are pitted with oil glands, have a strong mint odor. The narrowly oblong leaves are about 1 inch long, have (more)

 

*Dicerandra cornutissima 

Dicerandra cornutissima, or longspurred mint, is a strongly aromatic plant. It is a short-lived perennial that grows from seed. It can grow up to 1.6 feet tall with the erect, non-woody flowering shoots growing from a woody base. The linear leaves are about 1/2 of in an inch long, covered with (more)

 

*Dicerandra frutescens 

Dicerandra frutescens is very similar in appearance to D. chrismanii, but D. frutescens, or scrub mint as it is often called, has a minty aroma rather than a menthol smell. The scrub mint, a short-lived perennial, grows from a deep, stout, spreading-branching taproot to a height of 50 cm. Its (more)

 

*Dicerandra immaculata 

Lakela's mint is a small, fragrant, perennial shrub that reaches a height of 50 cm. It was listed in 1985 as federally threatened, and faces a high risk of extinction because so much of its habitat has been lost and its populations are so fragmented. This species is known from only one wild (more)

 

*Diervilla rivularis 

Diervilla rivularis is a North American shrub named in compliment of a French traveler, N. Dierville, who first brought the plant from Canada to Europe in 1699 (Small 1933, Fernald 1949). There are three Diervilla species, all of them eastern North American: D. lonicera, D. sessilifolia, and D. (more)

 

*Diervilla sessilifolia 

Diervilla sessilifolia is a North American shrub named in compliment of a French traveler, N. Dierville, who first brought the plant from Canada to Europe in 1699 (Small 1933). There are three Diervilla species, all of them eastern North American: D. lonicera, D. sessilifolia, and D. rivularis (more)

 

*Digitaria pauciflora 

Digitaria pauciflora is a blue-green to gray bunch grass that forms mounds of up to one meter (three feet) in diameter. Much of what is known regarding Digitaria pauciflora is taxonomic in nature (e.g. Hitchcock 1935; Webster and Hatch 1990; Wunderlin 1998). It is generally agreed upon that this (more)

 

*Dodecahema leptoceras 

Slender-horned spineflower is a federally-endangered, small, spreading annual in the buckwheat family (Polygonaceae), with stems reaching 3-15 cm across. The size of spineflowers varies, however, depending on annual available moisture (Ferguson et al. 1996). This annual has a basal rosette of (more)

 

*Dodecatheon austrofrigidum 

The frigid shooting star (Dodecatheon austrofrigidum) is a seemingly delicate plant that makes its home in some tough neighborhoods. Known from only eight locations, this rare shooting star is only found on ridges and steep basalt slopes along cold rivers in western Oregon and Washington. In (more)

 

*Dodecatheon dentatum var. utahense 

The Utah Shooting Star (Dodecatheon dentatum var. utahense) remains dormant during the winter. During the summer this attractive plant occurs in shady moist rock outcrops. This perennial is 1-2.5 dm tall. The flowers are violet to pink and sometimes white. There are 5 petals that are fused at (more)

 

*Downingia concolor var. brevior 

The Cuyamaca Lake downingia is a soft stem annual that germinates only when inundated with water when temperatures are cool. Downingias are one of an important and unique suite of plant and animal species that have adapted to thrive only within a vernal (seasonally moist then turning completely (more)

 

*Draba asterophora var. asterophora 

Draba asterophora Payson var. asterophora is a perennial forb in the Brassicaceae family. Its leaves are obovate, thick, and have entire margins. It has yellow petals and flowers from July through (more)

 

*Draba maguirei var. burkei 

Burke’s draba (Draba burkei) is a small leafed, small flowered perennial that lives high in the Uinta Mountains in northeastern Utah. Burke’s draba was only recently described as a separate species from Draba maguirei var. burkei (Windham 1998). Changing this taxon to a full species from a variety (more)

 

*Draba weberi 

A perennial herb with erect stems about 2-10 cm long, and with yellow flowers in bloom in June and July. Draba weberi may differ from other species in its wetter habitat of stream edges, but the possibility that it can survive in less mesic areas cannot be ruled out.

(more)

 

*Dubautia latifolia 

branched, woody (more)

 

 

*Dudleya abramsii ssp. parva 

This species is threatened by a number of urban development activities, and is limited to only eleven sites in the wild. It was listed as Federally Endangered by the U.S. Fish and Wildlife Service in 1997. (USFWS 1997) This species occurs in a very unique habitat, and is unique even among other (more)

 

*Dudleya blochmaniae ssp. blochmaniae 

Very little is known about Dudleya blochmaniae ssp. blochmaniae, or Blochman's dudleya, but its close relatives, other subspecies of D. blochmaniae, have been considered for Federal protection. These species include the short-leaved dudleya (D. blochmaniae ssp. brevifolia) and the Santa Rosa (more)

 

*Dudleya brevifolia 

The short-leaved dudleya is a small, rare succulent perennial plant that produces a rosette of leaves from a corm. White flowers with red or purple markings are borne on short stalks. Proposed for Federal protection in 1993, this species was removed from the candidate list in 1996, as it is one (more)

 

*Dudleya densiflora 

Dudleya densiflora is a succulent perennial that is distinguished from other dudleyas by its thick, linear, terete leaves that are covered in a mealy powder. It is also distinguished from other more common dudleyas by its light-colored flowers, often white to pink. This plant has a narrow range (more)

 

*Dudleya nesiotica 

Santa Cruz Island liveforever occupies an area of about 13 hectares (32 acres) on the west end of Santa Cruz Island. Plants are summer dormant, surviving by means of corms 10-30 mm in diameter. Leaves appear after the first winter rains and senesce coincident with flowering in April and May. Each (more)

 

*Dudleya stolonifera 

This rare plant is considered endangered by the World Conservation Union (IUCN) and listed in Appendix I of the Convention on the International Trade in Endangered Species (CITES). In this designation, Dudleya stolonifera joins the ranks of other endangered species such as tigers, Asian elephants, (more)

 
*Dudleya traskiae 

 

*Echinacea laevigata 

Smooth-purple Coneflower is an herbaceous perennial closely related to the common Purple Coneflower. The leaves of Smooth-Purple Coneflower, which are never cordate (heart shaped), distinguish the two in the field. It is a rhizomatous perennial herb with a fleshy rootstock and coarse, lanceolate, (more)

 

*Echinacea tennesseensis 

The Tennessee coneflower is one of the nation's rarest wildflowers (Clark 2000). Known only from five populations within a 14 mile radius in Middle Tennessee, it was the second plant listed as endangered by the U.S. Fish and Wildlife Service in June 1979 (USFWS 1989).
First listed in the
(more)

 

*Echinocactus horizonthalonius var. nicholii 

Echinocactus horizonthalonius var. nicholii is a small, long lived cactus found in southeastern Arizona. This bluish-green cactus produces intense pink flowers. Developing flowers are shaded by whitish-yellow wool that is nestled between radial spines. When fruits open, the rough black seeds (2 mm (more)

 

*Echinocactus mariposensis 

Echinocactus mariposensis is a solitary, diminutive-sized cactus that grows to only about 10-15 cm tall, and 8 cm in diameter at maturity. The plant has a grayish appearance overall, and on closer inspection, delicate, brown-tipped central spines can be seen arising from the many-spined (more)

 

*Echinocereus chisoensis var. chisoensis 

Echinocereus chisoensis is a short, columnar cactus with dark green, relatively soft stems. The plants can be single or multiple-stemmed and can grow up to nine inches in height. Towards the top of the stems incredibly spectacular flowers appear in tri-colored shades of pink between April and (more)

 

*Echinocereus reichenbachii var. albertii 

Black Lace Cactus is a small ornamental cactus with landscape value. It has large pink to light purple flowers (Merritt, pers. comm.). Variety albertii grows in south Texas along the Gulf Coast in only three counties. Over the years it has been over-collected due to its beautiful flowers. Like (more)

 
*Echinocereus reichenbachii var. fitchii 

 

*Echinocereus triglochidiatus var. arizonicus 

The Arizona hedgehog is a multi-stemmed columnar cactus up to 40 cm tall, with 10 tuberculate ribs. There can be up to fifty stems in a single clump, but it is more common to find clumps with 5-10 stems. Along the ribs, at growing points called ‘areoles’, clusters of 1-3 gray or pinkish central (more)

 

*Echinocereus viridiflorus var. davisii 

This diminutive cactus was first discovered in Texas by Arthur Houghton in 1931. Echinocereus viridiflorus var. davisii can grow up to 3 cm in diameter, with stems that are attractively marked with regularly spaced purplish horizontal stripes (Dorrel and Johnson 1970). Yellow-green flowers grow (more)

 

*Echinodorus parvulus 

Echinodorus parvulus is a small delicate plant that grows with its leaves submerged in the waters of shallow ponds. It grows to only 4 inches tall, with creeping shoots. Plants produce two to eight pinkish-white flowers that bloom from July to September. Fruits form in the mid to late fall, and (more)

 

*Echinomastus erectocentra var. erectocentra 

Echinomastus erectocentrus var. erectocentrus is a small cactus that can grow up to 6 inches in height. Plants have central spines that point upward. Variety erectocentra and var. acunensis are virtually indistinguishable, and may not be taxonomically distinct, according to Dr. Don Pinkava of (more)

 

*Echinomastus erectocentrus var. acunensis 

Cactus with solitary stems 7.5-15.0 cm tall and 7.5-10 cm wide, gray-green in color. A groove extends from the aereole to the base of each tubercule. Spines are distinctive. Radial spines 11-15 per cluster, up to 2.5 cm long, reddish to yellowish with dark tips. Central spines are 1.88-3.45 cm (more)

 

*Elymus svensonii 

Cactus with solitary stems 7.5-15.0 cm tall and 7.5-10 cm wide, gray-green in color. A groove extends from the aereole to the base of each tubercule. Spines are distinctive. Radial spines 11-15 per cluster, up to 2.5 cm long, reddish to yellowish with dark tips. Central spines are 1.88-3.45 cm (more)

 

*Enceliopsis nudicaulis var. corrugata 

Enceliopsis nudicaulis var. corrugata is an endemic species found on alkaline and saline soils that are restricted to Ash Meadows National Wildlife Refuge.

This is a perennial forb that produces a number of leafless flowering stalks, each supporting an individual yellow flower.
(more)

 

*Epipactis gigantea 

Epipactis gigantea is a tall perennial orchid that grows from creeping rhizomes. The one or more stems are 30 to100cm tall and are essentially hairless until the inflorescence, when they become pubescent. There are usually ten or more green leaves per plant, that alternate up the stem. Each leaf is (more)

 

*Epithelantha bokei 

Epithelantha bokei is a beautiful, low growing cactus covered so densely with hair-spines that plants appear completely white. These cacti are partially submerged in the ground, with 2-3 cm of stem height above ground level (Correll and Johnson 1970). During drought periods, plants draw back (more)

 

*Eriastrum densifolium ssp. sanctorum 

This endangered blue-flowered phlox species is restricted to sandy floodplain areas in Southern California and was listed as Federally Endangered in 1987. Remaining populations are threatened by flood control and competition with a non-native species, river cane (Arundo donax). In 1988, a (more)

 

*Erigeron basalticus 

These daisy-like flowers live exclusively in cracks and crevices in basalt cliffs in the state of Washington. Erigeron basalticus has several stems that originate in a taproot. Stems are generally 4-6” in length and leafy especially toward the tips. The majority of the leaves are tri-lobed at (more)

 

*Erigeron decumbens var. decumbens 

Today, less than one present of Prairie land in the Willamette Valley remains in western Oregon and southwestern Washington. Consequently, the once common Willamette daisy (Erigeron decumbens ssp. decumbens) has nearly become extinct.

Not seen since 1934, Erigeron decumbens ssp.
(more)

 

*Erigeron kachinensis 

Erigeron kachinensis was first found in the seeps in the Cedar Mesa sandstone near Kachina Natural Bridge in Natural Bridges Monument, Utah. It was first discovered in Colorado in 1977 within the Dolores River Canyon. Only two populations are currently known in the state. It will grow only where (more)

 

*Erigeron maguirei var. maguirei 

Erigeron maguirei var. maguirei is no longer recognized as a true variety, as DNA analysis was not able to show any variation between the formerly recognized varieties E. maguirei var. maguirei and E. maguirei var. harrisonii (Van Buren 1993). This was supported by the recently published volume 5 (more)

 

*Erigeron rhizomatus 

Zuni fleabane is a rare regional endemic with three known, yet widely scattered population centers in western New Mexico and northeastern Arizona. Zuni fleabane is distinct from other Erigerons by its rhizomatus habit, nearly hairless seeds, and very few hairs on the stems and leaves. The (more)

 
*Eriocaulon kornickianum 

 

*Eriocaulon parkeri 

This small, herbaceous aquatic plant has a rosette of delicate, grass-like leaves and tiny, white flowers. It occupies fresh to brackish tidal river shores and deltas along the east coast of the United States and Canada. The plant once occurred from Quebec south to North Carolina. However, the (more)

 

*Eriodictyon capitatum 

Shrub less than 3 m tall. Twigs glabrous and sticky. Linear, entire leaves to 9 cm with rolled margins. Upper leaf surface sticky, lower tomentose. Head-like inflorescence, with funnel-shaped, lavender corolla and linear, hairy (more)

 

*Eriogonum argophyllum 

During the 1990's this species was proposed for listing as federally endangered because the one known population was on unprotected property and threatened by a number of activities, including geothermal development that proposed to divert the surface water and lowering the water table that this (more)

 

*Eriogonum brandegeei 

Eriogonum brandegeei (also spelled ‘brandegei’), Brandegee’s wild buckwheat, is a 10-25 cm tall perennial. It has an unbranched, scapose, and tomentose flowering stalk and leaves which are densely tomentose on both sides. It blooms from July to August with white to pinkish or yellow flowers, and (more)

 

*Eriogonum codium 

An ironic legacy of the Cold War is that some of the best remaining habitats for many native and endangered species are on military bases or other government properties. Artillery ranges, training grounds, and secure land surrounding bases, ammunition depots and other top-secret or dangerous areas (more)

 

*Eriogonum coloradense 

Eriogonum coloradense is a matted, densely caespitose herbaceous perennial with a thick central taproot and spreading branches borne from a subterranean woody caudex. Mats are typically 5 to 15 centimeters in diameter (Reveal 1969) but may get as large 60 centimeters in diameter (Colorado Natural (more)

 

*Eriogonum corymbosum var. nilesii 

Eriogonum corymbosum var. nilesii is a plant of the Mojave desert. Known from the Las Vegas and Muddy Mountains region of Clark County, Nevada. Also from the flood plain of the Paria River in Kane County, Utah. Its status is candidate due to the loss of habitat from development. (more)

 

*Eriogonum crosbyae 

With just over 160,000 individuals in Nevada and over 16,000 in Oregon (Kaye et al. 1990 and NNHP 2001b), it is natural to wonder why scientists and land managers are concerned about this species. Despite this large number of plants, over 85% of the populations in Nevada lie within a mining (more)

 

*Eriogonum diatomaceum 

Eriogonum diatomaceum is only known from a few scattered populations in the Churchill Narrows area south of Fort Churchill State Park in Lyon County, Nevada. It is considered a “sensitive” species in Nevada and is also a candidate for federal endangered listing (Flora of North America Committee, (more)

 

*Eriogonum ephedroides 

This pretty little plant has only been found in four counties in Utah and Colorado, where it is vulnerable and imperiled. Ephedra buckwheat is the common name for Eriogonum ephedroides because its green loosely branching flower stalks resemble the Ephedra or “Mormon tea” plant. This plant is (more)

 

*Eriogonum gypsophilum 

Eriogonum gypsophilum, known commonly as gypsum wild buckwheat, has only three known populations, all exclusively located in Eddy County, New Mexico. Populations are limited to growing on a specific soil composition, gypsum, a mineral commonly used in drywall and plaster. This area of New Mexico is (more)

 

*Eriogonum ovalifolium var. vineum 

Cushenbury buckwheat is a low, densely-matted perennial herb endemic to carbonate deposits on the north side (desert side) of the San Bernardino Mountains (Transverse Ranges) of San Bernardino County, California. Cushenbury buckwheat is a "cushion" plant reaching 10-20 inches (2.5 - 5 dm) in (more)

 

*Eriogonum ovalifolium var. williamsiae 

Extreme habitat specificity limits Steamboat buckwheat to less than 250 acres in Nevada. Here it grows in the forbidding conditions surrounding thermal Hot Springs. This is the sole location of this endangered plant in the entire world. It is listed as Endangered by the U.S. Fish and Wildlife (more)

 

*Eriogonum pelinophilum 

Clay-loving wild buckwheat is a low, rounded sub-shrub arising from a woody taproot. Its flowers are white to cream, blooming in June and July. It has numerous woody branches from which bark hangs off in loose strips. The plant is found in sparsely vegetated shrub-lands and on barren adobe clay (more)

 
*Eriogonum ripleyi 

 

*Eriogonum visheri 

The gullied ridges and eroded hills of South Dakota's Badlands National Park have the character of a moonscape. Almost no plant life can be found on these barren slopes, except the Dakota wild buckwheat, a wiry, inconspicuous little plant that makes a home in the badlands of North and South Dakota (more)

 

 

*Eryngium aristulatum var. parishii 

San Diego button celery is an annual herb from the parsley family and is often recognized by its low spreading appearance and greenish flowers. It once occurred in many vernal pool systems, but by the late 1980's 23% of vernal pool systems had been destroyed, leaving remaining populations (more)

 

*Eryngium constancei 

Loch Lomond button-celery is a low-growing annual herb with tiny white to light purple flowers found only in northern California. This species grows in the bed of a small vernal lake, surrounded by a ponderosa pine and black oak forest, in the Loch Lomond Ecological Reserve in Lake County. (more)

 

*Eryngium cuneifolium 

Eryngium cuneifolium is an aromatic perennial herb found on the southern Lake Wales Ridge in Highlands County, Florida. It has a long, woody taproot and a persistent rosette of dark green leaves. These leaves are long, stalked, and shaped like narrow wedges. With several erect and branching (more)

 

*Erysimum capitatum var. angustatum 

This species is considered a desert relic type that, along with a small group of other plant species, forms the base of the unique plant community found at Antioch Dunes. These dunes were declared critical habitat for both this wallflower and the rare Antioch Dunes evening-primrose (Oenothera (more)

 

*Erythrina eggersii 

Erythrina eggersii is a spiny tree known only from Puerto Rico and the U.S. Virgin Islands (USFWS 1996). Currently, fewer than 75 plants remain in the wild (CPC (more)

 

*Erythronium elegans 

Erythronium elegans presents something of a paradox. It is a geographically highly restricted, very rare plant, that also an ecological generalist. It has been found growing in only five localities, all in the northern Coast Range of Oregon. Even within particular populations, they can be found (more)

 

*Erythronium propullans 

This plant is a spring ephemeral, showing itself in only fourteen populations in the woods of Minnesota during the months of April and May and disappearing from sight by early June. This plant is a mystery, as it is very rarely found producing seeds. It grows from a bulb with an underground (more)

 

*Eugenia koolauensis 

Eugenia koolauensis is a member of the myrtle family (Myrtaceae). It is a small tree or shrub, and can reach 2 - 7 meters (7 - 23 feet) in height. Its branch tips are covered with dense brown hairs and their leathery oval leaves are densely hairy on the lower surface. From February to December, (more)

 

*Eupatorium leucolepis var. novae-angliae 

Eupatorium leucolepis var. novae-angliae is a member of the daisy family (Asteraceae) and endemic to southeastern New England. Only sixteen populations are left in four counties of Massachusetts and Rhode Island. The taxon occurs almost exclusively in coastal plain ponds -- unique habitats in (more)

 

*Eupatorium resinosum 

Pine barrens boneset is a white-flowered, flat-topped 1m tall Eupatorium of wet places, notable for being glandular and pubescent more or less throughout (Godfrey & Wooten 1981; Cronquist 1980; Radford et al. 1968). John Torrey collected a specimen from New Jersey in 1835 and recognized it as being (more)

 

*Euphorbia haeleeleana 

Euphorbia haeleeleana, is a short-lived perennial that is a member of the spurge family (Euphorbiaceae). It is a small dioecious tree 3 to 14 meters (10 to 46 ft) tall. It has thick branches and alternate, elliptic papery leaves 10 to 15 centimeters (4 to 6 in) wide. The male trees have many (more)

 

*Euphorbia purpurea 

This handsome, stout perennial is found in rich stream valleys of the Appalachian belt of the eastern United States from Delaware to Ohio and West Virginia. This species is rare throughout its range, and wetland alteration, grazing by deer and livestock, and trampling by recreational activity pose (more)

 

*Euphorbia telephioides 

Euphorbia telephioides is a perennial herb found only in Gulf, Franklin, and Bay counties, Florida in the Florida panhandle. It has numerous stems, giving it a bushy appearance, and flowers are reddish-green cup-like structures that appear from April through July. Fruit is a three-lobed capsules. (more)

 

*Eutrema penlandii 

Eutrema penlandii is a small herbaceous perennial usually found on south- and east-facing flat to gently sloping benches with steep walls that provide some protection from snow-melting winds (Smith 1993). This species is an ice age relict; its closest relative is the arctic species, E. edwardsii, (more)

 

*Festuca ligulata 

Festuca ligulata is a loosely tufted perennial grass growing up to 32 inches in height (Hitchcock 1950, Gould 1975). The slender stems of this grass are roughly textured and curve upward from a rhizomatous base. Inflorescences are branched and droop delicately. Festuca inhabits rocky, steep sites (more)

 

*Flueggea neowawraea 

Flueggea neowawraea, a member of the spurge family (Euphorbiaceae) is the only member of its genus in Hawai’i. It is most often dioecious (bearing either male or female flowers) tree that requires cross-pollination in order to produce viable seed. However, there is evidence that this species is (more)

 

*Forestiera segregata var. pinetorum 

Forestiera segregata is a shrubby-tree that can grow up to ten feet in height. It has smooth, pale bark and a dense crown made up of opposite two-colored leaves (shiny, dark green above & dull below) (Scurlock 1992). The flowers are small, greenish-yellow, and composed mostly of showy stamens. The (more)

 

*Forsellesia texensis 

Forestiera segregata is a shrubby-tree that can grow up to ten feet in height. It has smooth, pale bark and a dense crown made up of opposite two-colored leaves (shiny, dark green above & dull below) (Scurlock 1992). The flowers are small, greenish-yellow, and composed mostly of showy stamens. The (more)

 

*Fothergilla major 

Fothergilla is a genus native to the southeastern United States. F. major, the large fothergilla, is a densely branched colonial shrub. Its usual height is 6 ft, although it may grow in the wild to 10 and even nearly 20 ft (Small 1933, Weaver 1971). Fothergilla gardenii, the small fothergilla, is (more)

 

*Frasera coloradensis 

Geological activity in southeastern Colorado has exposed rock formations buried more deeply in other parts of the plains. The Greenhorn Limestone is one of them, outcropping in a scattering of gentle hills and ridges that appear barren from a distance. The unique chemistry of limestone limits the (more)

 

*Frasera gypsicola 

Frasera gypsicola is primarily found on Pleistocene gypsum spring mounds in Nevada. It is a pale green perennial forb with a short, wide root-crown from which arise many branches pressed tightly together. Leaves are always opposite, close-together and grass-like and form a mound at the plant’s (more)

 

*Fremontodendron decumbens 

This species of flannelbush cannot self-pollinate but has a fascinating relation with the three native bee species that pollinate its flowers. The bees are attracted to the high levels of ultraviolet light the flowers reflect. The nectar they produce absorbs UV light (appearing darker to the bees) (more)

 

*Fremontodendron mexicanum 

Fremontodendron mexicanum is a tree like shrub with bright orange flowers that bloom between March and August. The showy plant is often used as an ornamental shrub in gardens. Currently, fewer than 100 individuals are known from sites in two areas, southern San Diego County and Estado de Baja (more)

 

*Fritillaria gentneri 

For a short but glorious time each spring, the solitary, almost sculptural waxy-blue stems, with their clusters of dagger-like leaves, of Gentner's fritillary are festooned with striking purplish-red bell-like flowers, themselves decorated with a loose checkerboard streaking of yellow spots. The (more)

 

*Fryxellia pygmaea 

For a short but glorious time each spring, the solitary, almost sculptural waxy-blue stems, with their clusters of dagger-like leaves, of Gentner's fritillary are festooned with striking purplish-red bell-like flowers, themselves decorated with a loose checkerboard streaking of yellow spots. The (more)

 

*Gaillardia aestivalis var. winkleri 

The white firewheel is a rare relative of roadside wildflowers called Indian blanket or Mexican blanket. This rare species flowers from May to September with 12-18 deeply-three-lobed white to maroon ray flowers or "petals" (as opposed to yellow and orange) and with a yellow or purple "eye" of disk (more)

 

*Galactia smallii 

Galactia smallii is a delicate, trifoliate sprawling herb with pink or lavender pea-like flowers (Avery and Loope 1980, Herndon 1981, Isley 1990). It is endemic to Miami-Dade County's rare pine rockland ecosystem (Hainds et al. 1999, Coil 2000, Fisher 2000). Currently, G. smallii is known from (more)

 

*Gardenia brighamii 

Gardenia brighamii is endemic to the Hawaiian Islands and at one time thought to have occurred on all of the main islands. Judging from its use by the Hawaiians as a cloth dye, its habitat, associated species, and distribution in the early 1900s, it was probably a relatively common member of the (more)

 

*Gardenia mannii 

This member of the coffee family is a tree that grows to a height of up to 50 ft (15 m). Lance- to elliptic-shaped leaves have a sticky, glossy upper surface, and are clustered toward the tips of branches. Solitary flowers form at branch ends and are cream/white colored. These fragrant blossoms (more)

 

*Gaura neomexicana ssp. coloradensis 

The meadows that hug stream banks on the plains of southeastern Wyoming and adjacent Colorado and Nebraska are lush compared to the shortgrass prairie of the surrounding uplands. These refreshing places are the last stand of the Colorado butterfly plant, a plant threatened with extinction due to (more)

 

*Gaussia attenuata 

This tree has a slender trunk and grows near the summits of limestone hills on the northern coast of Puerto Rico. Because it is usually taller than the surrounding trees, the species is readily identified at a distance. (University of Puerto Rico (more)

 

*Gaylussacia brachycera 

The box huckleberry is a dwarf (1-4 dm) evergreen shrub that forms large, solid-mat, self-sterile colonies, each one appearing to consist of a single clone that may extend over 8 acres! One colony in Perry county Pennsylvania (the Amity-Hall area) is about a mile long. It appears to be a single (more)

 

*Genistidium dumosum 

Genistidium dumosum is a small shrub known from only three locations in in the United States (Poole 1982). G. dumosum is not protected because additional populations are thought to occur in Mexico (Poole 1989). Leaves are drought-deciduous and appear only after a rain. This habit gives the shrub (more)

 

*Gentiana bisetaea 

Genistidium dumosum is a small shrub known from only three locations in in the United States (Poole 1982). G. dumosum is not protected because additional populations are thought to occur in Mexico (Poole 1989). Leaves are drought-deciduous and appear only after a rain. This habit gives the shrub (more)

 
*Gentiana setigera 

 

*Geocarpon minimum 

If you want to see Geocarpon minimum you'll need good eyes and good knees! That's because this plant is TINY, and to find it often requires getting down on hands and knees. Growing between one and four centimeters tall, G. minimum is the only member of its genus, making it a very unique member of (more)

 

*Geum geniculatum 

Bent Avens is endemic to the southern Appalachians and is found on only a few high peaks in North Carolina and Tennessee. It is speculated that past climate changes are the reason for its limited distribution. A warming/drying period may have made all but the highest, wettest mountains (more)

 

*Geum peckii 

This alpine-boreal member of the Rose family can be found growing along mountain streams and rocky wet meadows, as well as bogs and sphagnum-moss depressions. Known from only two places in the world -- the Presidential Mountain Range of New Hampshire, and Digby County in Nova Scotia -- the species (more)

 

*Geum radiatum 

Spreading avens is a rare endemic found on a few mountaintops in the Southern Appalachians. This species has received a great deal of attention over the past few decades from government organizations and conservationists who have called attention to the problems facing it’s continued survival. (more)

 

*Gilia caespitosa 

Gilia caespitosa is a perennial forb in the phlox family. Flowers bloom in July and vary fro in color from a bright scarlet to a bluish-blue purple. The leaves that form a dense base are entire or few-lobed and sticky. Seed is set in late July or August. (Atwood 1991).

Because of its
(more)

 

*Gilia sedifolia 

A perennial, taprooted herb with a basal rosette of leaves. Leaves are succulent, linear. Flowers are borne in a spikelike cluster.


(more)

 

*Glaucocarpum suffrutescens 

A perennial herbaceous plant with clumped stems arising from a branching woody root crown. The flowers are light yellow or green-yellow in a raceme (cluster) at the end of the (more)

 

*Goetzea elegans 

Beautiful trumpet shaped orange flowers are the crowning glory of Goetzea elegans, an evergreen shrubby tree that can grow up to 9 meters in height (USFWS 1990). Until recently, flowers had not been observed on any plants of this species since 1936 (USFWS 1984). This species is only found in the (more)

 

*Gouania hillebrandii 

There are two endangered Gouania species endemic to Hawai’i (U.S. Fish and Wildlife Service [USFWS] 2001). G. hillebrandii, a member of the Buckthorn family (Rhamnaceae) is an erect to sprawling shrub that has pale to brown pilose stems with elliptic blades. The sweet fragrant flowers of G. (more)

 
*Graptopetalum bartramii 

 

*Grindelia fraxinopratensis 

G. fraxinopratensis is an erect biennial - perennial forb, reaching 25 to 40 inches in height and has yellow flowers. This xeric adapted species flower during summer and fall. It can be found primarily in saltgrass meadows along streams and surrounding pools and occasionally on open alkali clays (more)

 
*Grindelia oolepis 

 

*Gutierrezia elegans 

Subshrub, 7.5-12.5 cm high. The species is quite lovely and dainty in its symmetrical abundance of long-lived, bright, yellow flowers.

(more)

 

*Hackelia cronquistii 

Although Hackelia cronquistii can be quite showy, it has historically been overlooked. This perennial herb can range in size from about 6 inches to 2 feet tall (15-60 cm). Its small blue-tinged white flowers put on an attractive display. It was first collected in 1896, but only one population (more)

 

*Hackelia venusta 

Hackelia venusta makes up for its short stature, being only 8-16 in. (20-40) cm tall, by a splashy display of large, showy white flowers. This beautiful plant is the rarest in Washington, found at only one site in the entire state, and nowhere else in the world. The Showy stickseed is restricted (more)

 

*Haplostachys haplostachya var. angustifolia 

There are five recorded species of Haplostachys endemic to Hawai’i, but only one remains today, and that is H. haplostachya (U.S. Fish and Wildlife Service [USFWS] 2001).

This taxon, a member of the mint family (Lamiaceae), is an erect perennial herb that has square stems with dense
(more)

 

*Harperocallis flava 

When not flowering, Harperocallis flava, or Harper's beauty, appears very grass like, and can easily be overlooked. The leaves of the rhizomatous, perennial herb are stiff and grassy, 5 to 21 cm tall. However, when this plant flowers, you know why its known as Harper's beauty. This plant's (more)

 

 

*Hastingsia bracteosa 

This lily with long, slender leaves can be found with both purple and white flowers. White-flowered plants (Hastingsia bracteosa var. bracteosa) are found in the north of the 12-mile (20-km) range while purple-flowered plants (var. atropurpurea) are found in the south (Lang and Zika 1997). These (more)

 

*Hedeoma diffusum 

Flagstaff pennyroyal is a small perennial herb which forms circular prostrate mats with numerous shoots. Its small leaves are arranged oppositely on delicate square stems. The small, irregular blue-lavender flowers can be found from late May to September, and are borne in clusters of 1-3 in leaf (more)

 

*Hedeoma todsenii 

Todsen's pennyroyal is a rare mint that is found in south-central New Mexico. It is a perennial rhizomatous herb approximately 4 to 8 inches (10 to 20 cm) tall. The small, lance-shaped leaves are arranged oppositely along the stem. The tubular orange (or less frequently yellow) flowers open to (more)

 

*Hedyotis purpurea var. montana 

Roan Mountain bluet is a rare endemic found on a few mountains in the Southern Appalachians. A member of the coffee family (Rubiaceae), Roan Mountain bluet produces heterostylus flowers (two different length styles). This species is a compact clump forming perennial herb and produces flat top (more)

 

*Hedyotis st.-johnii 

Species in the genus Hedyotis are members of the coffee family (Rubiaceae). There are 17 recorded taxa of Hedyotis and, of these, 14 are threatened or endangered, and one is extinct. H. st.-johnii (Na Pali beach hedyotis) is a Federally endangered species, with only four populations containing (more)

 

*Helenium virginicum 

Ah-choo! An allergic reaction to Helenium? No! The sneezeweed got its name from early settlers who would dry the yellow flower heads and grind them into a snuff. People sniffed the snuff to make them sneeze and open stuffy noses.
At the time that Helenium virginicum was listed as federally
(more)

 

*Helianthemum greenei 

Flowers have 5 bright yellow petals and are about 2 cm in diameter. One-year-old plants with 1-5 flowers may be only 10-15 cm tall. However, mature plants may reach 0.5 m in height, producing up to 100 flowers on multiple branches, and may live for up to 10 years. The minute, black, globose seeds, (more)

 
*Helianthus carnosus 

 

*Helianthus niveus ssp. tephrodes 

This beautiful sunflower grows in Dune ecosystems of California. Plants are perennials form long tap roots and can grow up to one meter in height. The leaves are all opposite or nearly alternate, and spathulate, with white, or grayish sericeous hairs appressed on the surfaces. The flower heads are (more)

 

*Helianthus paradoxus 

Sunflowers are an important part of the floral and cultural heritage of Texas and the United States, which is rapidly being lost due to neglect. Because our wild sunflowers are in the same genus as our domestic sunflowers, their genes could be invaluable in improving characteristics (e.g., yield, (more)

 

*Helianthus schweinitzii 

Almost all of the extant populations of this native sunflower are on vulnerable sites. Protection from shade and competition from other vegetation have been identified as the most important habitat characteristics for Helianthus schweinitzii. Unfortunately, the habitat that meets these requirements (more)

 

*Helonias bullata 

This beautiful plant is locally abundant in areas along the east coast. Despite this, most existing populations are unprotected and suffer from known direct threats to their existence. There is a great deal of public interest in this plant due to its attractive bright pink clusters of spring (more)

 

*Hemizonia minthornii 

Hemizonia minthornii, or Santa Susana tarplant, is a perennial subshrub in the aster family that produces yellow flowers from July to November. It grows in crevices of sandstone bluffs and outcrops in the chaparral in the Santa Susana and Santa Monica mountains of Los Angeles and Ventura (more)

 

*Hemizonia mohavensis 

Hemizonia mohavensis was considered extinct for over 50 years, as historical collections of this plant came from a three locations, including one in the San Jacinto Mountains and another on a sand bar along the Mojave River on the north slope of the San Bernardino Mountains in San Bernardino (more)

 

*Heritiera longipetiolata 

This beautiful buttressed tree grows to a height of 40 feet, with mottled tan bark. Leaves are silvery below and dark green above. The petioles, about 2 inches long are twice as those of the common street tree, H. littoralis whose leaves are more elongated. The fruit is about 2 - 3 inches long by 2 (more)

 

*Hesperomannia arbuscula 

Hesperomannia arbuscula is a member of a rare and endemic genus found in the dry forest areas of the south and central Wai`anae Mountains on O`ahu and Iao Valley on Mau`i. On O`ahu, the 3 remaining populations is known to occur within an area of only about 10 square miles. It is a small, shrubby (more)

 

*Heuchera maxima 

Heuchera maxima is a perennial herb in the saxifrage (Saxifragaceae) family. Heuchera maxima grows on moist, shady, north facing canyon bottoms, walls and seas cliffs in the northern Channel Islands, California. This species produces flowering stalks that can reach up to 6dm in length and is (more)

 

*Hibiscadelphus distans 

There are seven known species of Hibiscadelphus, which is a genus that is endemic to Hawaii. Five of those seven species are now extinct in the wild, although two of those are surviving in cultivation. H. distans is one of the two remaining Hibiscadelphus species with remaining wild populations. (more)

 

*Hibiscadelphus giffardianus 

There are seven known species of Hibiscadelphus, which is a genus that is endemic to Hawaii. Four of those seven species are now extinct. H. giffardianus, one of the remaining 3 species, was discovered in 1911, and is known from only one tree in the wild. In 1930, this tree died, but one cutting (more)

 

*Hibiscadelphus hualalaiensis 

There are seven species of Hibiscadelphus, an genus endemic to Hawaii, and four of those species are now extinct. H. hualalaiensis is one of the 3 remaining species, but is itself extinct in the wild, with only 22 plants surviving in cultivation today. The species was discovered in 1909 on the (more)

 

*Hibiscadelphus woodii 

There are seven known species of Hibiscadelphus, an genus endemic to Hawaii, five of which are now extinct in the wild. The recently discovered (Lorence 1995) H. woodii is one of the two Hibiscadelphus species with remaining wild populations. Unfortunately, this species appears to be heading for (more)

 

*Hibiscus arnottianus ssp. immaculatus 

There are eleven taxa of Hibiscus endemic to Hawaii, seven taxa are threatened with extinction and one is extinct. Hibiscus arnottianus is known for its beautiful white fragrant flowers. There are three recognized subspecies of H. arnottianus on the islands of Hawai’i, and the subspecies (more)

 

*Hibiscus brackenridgei ssp. brackenridgei 

Hibiscus brackenridgei is Hawai`i's State flower and a member of the mallow family (Malvaceae). It is a sprawling shrub to small tree with beautiful yellow flowers with a maroon spot in the center. Hibiscus brackenridgei ssp. brackenridgei is currently known only from 7 populations with a total of (more)

 

*Hibiscus brackenridgei ssp. mokuleianus 

Hibiscus brackenridgei is Hawai`i's State flower and a member of the mallow family (Malvaceae). It is a sprawling shrub to small tree with beautiful yellow flowers with a maroon spot in the center. Hibiscus brackenridgei ssp. mokuleianusis currently known only from 5 populations with a total of (more)

 

*Hibiscus clayi 

Hibiscus clayi is a member of the mallow family (Malvaceae). It is a shrub or tree up to 4 to 8 meters tall with stems bearing sparse hairs at the branch tips. The flowers are borne singly near the ends of the branches are dark red in color. Hibiscus clayi was known from scattered locations on (more)

 

*Hibiscus dasycalyx 

The Neches River rose mallow is a federally listed candidate endangered native Hibiscus that now only exists in three wetlands in E. Texas. This Hibiscus has delicate slender finely divided leaves on long, arching 3-7 foot long stems. The creamy white flowers are 3-6 inches wide with dark burgundy (more)

 

 

 

*Howellia aquatilis 

How can any plant found in California, Washington, Idaho and Montana, especially one with over 150 known occurrences, possibly qualify as Threatened under the Endangered Species Act? Howellia aquatilis is such a plant, and it richly deserves protection. Over two thirds of the known sites are (more)

 

*Hudsonia montana 

The golden heather represents a wonderful case of an endangered species where threats to its very existence became tools to help save it. There are very few of these plants left and hikers and rock-climbers passing through the species' habitat were damaging many of the remaining populations. Not (more)

 

*Hymenoxys texana 

Prairie dawn is a member of the sunflower family, but this small annual only reaches a height of seven inches and so is often overlooked. This plant is found only in the open grasslands of the northern part of the Gulf Prairie region of Harris and Fort Bend Counties of Texas. In late winter its (more)

 

*Hypericum cumulicola 

As a member of the genus Hypericum, this plant may contain hypericin, which is a promising chemical compound that may help protect animals from viral diseases. (Duke 1989) This species was listed as federally endangered in 1987, and the main causes of its decline include habitat loss, habitat (more)

 

*Ilex collina 

Ilex collina, a long-stalked holly, is a deciduous shrub of great ornamental potential. It is a multi-stemmed shrub growing to 10 feet, with large berries that range in color from dark scarlet-red to orange and yellow (Small 1933, Strausbaugh and Core 1978, Gleason and Cronquist 1991). (more)

 

*Iliamna remota 

Iliamna corei is an erect, ascending, perennial herb with dense pubescent branches and simple maple-like leaves with 5 to 7 palmate lobes. The attractive pink flowers are solitary or clustered in the axils of the upper leaves. One of the rarest native plants in the United States, Iliamna corei is (more)

 

*Iliamna rivularis var. rivularis 

The Kankakee globe-mallow was first described in 1906, and was originally found on an island in the Kankakee River in Illinois. In the 1920's it was recognized that this species was in danger of extinction, so seeds were collected and reportedly dispersed along railways in Illinois, Indiana, and (more)

 

*Ipomopsis globularis 

A perennial herb, 1.5 dm tall, with a strong, sweet fragrance. Produces white or pale purple flowers in a globe-like cluster surrounded by long, wooly hairs. Blooms July-early August.


(more)

 

*Ipomopsis polyantha var. polyantha 

Pagosa ipomopsis is an herbaceous perennial or possibly biennial that is a member of the Phlox Family. This species was first discovered and collected in 1899 by Charles Fuller Baker. It was originally described by Rydberg (1904) as Gilia polyantha and later moved into the genus Ipomopsis by (more)

 

*Ipomopsis sancti-spiritus 

Holy Ghost ipomopsis is known from a single 2-mile stretch of canyon east of Santa Fe, New Mexico. The population of approximately 2000 individuals has experienced decline in the past 6 years. Population viability models indicate that the species is headed toward extinction within the next 50 (more)

 

*Iris lacustris 

This miniature perennial iris has deep blue, sometimes lilac or white flowers (1 1/2 inches in width and 1 1/2-2 1/2 inches in height) that occur one flower per stem. Flowers appear from early May to early June, and have 3 petals with yellow crests. Stems are less than 2 inches tall. Leaves are (more)

 

*Isodendrion pyrifolium 

Isodendrion pyrifolium, or Wahine nono kula, was presumed extinct for over 100 years, until 1991, when four plants were found on State-owned land on the island of Hawai’i. This land was being developed for residential housing and a golf course. Further searches of the site added an additional 50 (more)

 

*Isoetes lithophila 

Isodendrion pyrifolium, or Wahine nono kula, was presumed extinct for over 100 years, until 1991, when four plants were found on State-owned land on the island of Hawai’i. This land was being developed for residential housing and a golf course. Further searches of the site added an additional 50 (more)

 

*Isoetes louisianensis 

Quillworts, relatives of ferns, live in or near lakes or streams, especially those with low nutrient content. Lacking stomata, quillworts take in carbon dioxide from the soil and collect the gas in four long, cylindrical air chambers inside their leaves. Quillworts are primitive, seedless vascular (more)

 

*Isoetes tegetiformans 

Mat-forming quillwort is a small, rooted aquatic emergent found in very shallow pools on granitic flat rock. Individual plants have a slender, centrally furrowed, prostrate azil ca. 1 mm thick. The population structure is dense and mat forming, with the adventitious buds cauline perennial fern (more)

 

*Isotria medeoloides 

Isotria medeoloides is a small, perennial orchid of deciduous forests with a grayish-green, smooth stem up to 30 cm tall that bears at its summit a whorl of 5-6 light-green, elliptical, pointed leaves and 1-2 yellow-green flowers. This distinctive leaf whorl gives the plant its name; only one (more)

 

*Ivesia kingii var. eremica 

Ivesia kingii var. eremica is an endemic species found on moist to saturated alkaline soils and also in saltgrass meadows. It is a perennial herb with white flowers. Its federal status is threatened. (more)

 

*Ivesia rhypara var. rhypara 

Ivesia rhypara var. rhypara is an unusual looking plant with an unusual name that grows on unusual soil. It is listed as Endangered by the State of Oregon and is on Nevada's watch list.

The substrate that this unusual plant is limited to is similar to known gold-bearing deposits in
(more)

 

*Ivesia webberi 

Ivesia webberi is a distinctive species that is not likely to be mistaken with other species. It is a perennial herb with greenish-gray foliage and dark red wiry stems. The flowers are yellow. Late in the season the whole plant becomes reddish-tinged. Its federal status is candidate. Until very (more)

 

*Jacquemontia reclinata 

A low (usually) growing vine found on the lee side of coastal sand dunes with white, star-shaped flowers (Small 1934, Martin 1994, Garvue 1999). The habitat for this plant is very rare and threatened by coastal development and rise in seas (more)

 

*Justicia cooleyi 

Cooley's water-willow is a small but lovely plant. It is a short, rhizomatous, perennial herb that grows to less than 40 cm (16 inches) tall. Justicia cooleyi has upright, square stems that are covered with hairs. Its flowers, which open from August to December, are borne on forked, zigzag (more)

 

*Kallstroemia perennans 

Cooley's water-willow is a small but lovely plant. It is a short, rhizomatous, perennial herb that grows to less than 40 cm (16 inches) tall. Justicia cooleyi has upright, square stems that are covered with hairs. Its flowers, which open from August to December, are borne on forked, zigzag (more)

 

*Kalmia cuneata 

White wicky is endemic to the southeastern coastal plain, historically found in seven counties in North Carolina and three in South Carolina. Today, it is found at forty locations in all seven historically known counties North Carolina, but only one location in a single county in South Carolina. (more)

 

*Kokia cookei 

Kokia cookei is considered one of the rarest and most endangered plant species in the world. It was discovered in the 1860's on the western end of Moloka`i by Mr. R. Meyer. This find consisted of 3 tress, which were not relocated on subsequent visits a few years later. In 1910, a single living (more)

 

*Kokia drynarioides 

The Hawaii tree cotton is one of four species in the genus Kokia and the only one found on the island of Hawaii. The sap of this incredibly rare tree has been used by native Hawaiians to make red dyes for fishnets and its bark was used to treat thrush. In the early 1900's, botanists became (more)

 

*Kokia kauaiensis 

There are four described species of Kokia, a genus endemic to Hawaii. Of these four, one has been presumed extinct since the late 1800’s, and the other three are clinging to life with varying degrees of success. One of them, Kokia cookei, survives only in botanical gardens as a few individuals (more)

 

*Lantana canescens 

•Lantana canescens is short-lived perrenial shrub that can grow up to 2 meters tall.
•Leaves are up to 6.5 cm long, opposite, simple, lanceolate to elliptic-lanceolate, densely hairy on both surfaces.
•Flowers are white and tubular. They grow in flattened clusters at the ends of long
(more)

 

*Lasthenia burkei 

Lasthenia burkei is a herbaceous annual with narrow leaves and produces small clusters of whitish-yellow flowers. This aster grows in vernal pools and swales in Cotati Valley in Sonoma County, California.

Vernal pools, one of California's most threatened habitats, are natural
(more)

 

*Lavatera assurgentiflora ssp. glabra 

Lasthenia burkei is a herbaceous annual with narrow leaves and produces small clusters of whitish-yellow flowers. This aster grows in vernal pools and swales in Cotati Valley in Sonoma County, California.

Vernal pools, one of California's most threatened habitats, are natural
(more)

 

*Leavenworthia aurea var. texana 

A pretty little winter annual less than 1 dm tall. Leaves in a basal rosette, lyrately lobed with a large terminal lobe and several smaller lateral lobes, to about 5 cm long, glabrous, the terminal lobe usually wider than long, the margin usually angularly toothed. Flowers borne on scapes 3-9 cm (more)

 

*Leavenworthia crassa 

Not Available

(more)

 

*Leiophyllum buxifolium 

This species is found in three disjunct locations in the United States: the New Jersey Pine Barrens, the Coastal Plain of North and South Carolina, and the southeastern Blue Ridge Province. (Strand and Wyatt 1991) It has yet to be resolved if plants at these three locations are members of the (more)

 

*Leitneria floridana 

Leitneria floridana is the sole member of its genus and is found only on the Coastal Plain of the eastern United States. Corkwood’s scattered range includes freshwater swamps, wetland thickets, pond habitats, brackish tidal streams and brackish marshes of coastal southeast Texas, the central Gulf (more)

 

*Lepidium barnebyanum 

Lepidium barnebyanum is a perennial, herbaceous plant in the mustard family. This plant produces glabrous stems and narrow leaves clustered at the base of the plant. Cream-colored flowers begin blooming in April or early May (USFWS 1990).
Barneby Ridge-cress has been listed as Endangered
(more)

 
*Lepidium serra 

 

*Lespedeza leptostachya 

Prairie bush clover is an herbaceous perennial that is a member of the legume family. It is endemic to Midwestern tallgrass prairies, and is known from 36 sites in 4 states. This species is currently listed as federally threatened.

This particular clover produces a single stem that can
(more)

 

*Lesquerella congesta 

Lesquerella congesta, a herbaceous perennial, has bright yellow flowers that bloom in April and May in a dense cluster. Although the bright color stands out against the barren, white shale habitat, these plants are hard to see, being typically less than 2 cm across. A very long, thin taproot (more)

 

*Lesquerella filiformis 

Lesquerella filliformis is a winter annual. This means that it flowers and produces fruit in the early summer. Once hot weather arrives, plants disperse their seeds and die. These seeds lie dormant through the heat of the summer and germinate in the fall. They overwinter as a basal rosette, and (more)

 

*Lesquerella globosa 

Lesquerella globosa is a diminutive plant that is covered with dense hairs that give its leaves a gray-green appearance. The small flowers have beautiful spoon-shaped petals that are displayed from April to early June. The name of the plant is derived from the globe-shaped fruits it (more)

 
*Lesquerella kaibabensis 

 

*Lesquerella lyrata 

Not Available


(more)

 

*Lesquerella pallida 

The White bladderpod, a member of the Brassicaceae or Mustard Family, was first discovered on prairies within an unusual geological region called the Weches formation near San Augustine, Texas in the 1830's by M.C. Leavenworth but was not noticed again until 1981 by Nixon and Ward. White Bladderpod (more)

 

*Lesquerella parviflora 

In June and early July, Piceance Bladderpod produces golden-yellowish flowers off of decumbent stems from low growing rosettes. This bladderpod is covered with star-shaped hairs which gives it a silvery appearance. It is these specialized leaf hairs that separate this species from other closely (more)

 

*Lesquerella perforata 

Lesquerella perforata's common name, Spring Creek bladderpod, derives from the floodplain area in which it grows and the shape of its fruit. This rare plant is now known only from a small area within Tennessee's Central Basin. It's continued survival is threatened by practices that alter its (more)

 

*Lesquerella pruinosa 

The Pagosa Springs bladderpod, Lesquerella pruinosa, is a perennial plant and member of the Mustard family, and can grow 10-25 cm tall. It was named after the very short, dense hairs covering the leaves and stems to give the plant a frosted appearance. The diamond-shaped leaves are mainly basal, (more)

 

*Lesquerella stonensis 

The Stones River bladderpod is a showy member of the mustard family, producing fragrant white flowers. This rare annual requires habitat disturbance in order to complete its life-cycle. Historically, the floodplain habitat it was found in was maintained by regular flooding, which removed (more)

 

*Lesquerella thamnophila 

The Stones River bladderpod is a showy member of the mustard family, producing fragrant white flowers. This rare annual requires habitat disturbance in order to complete its life-cycle. Historically, the floodplain habitat it was found in was maintained by regular flooding, which removed (more)

 
*Lessingia germanorum var. germanorum 

 

*Liatris helleri 

Heller's Blazing Star is an extremely rare and attractive native wildflower. Its habitat consists of rocky outcrops, ledges, cliffs and balds at high elevations in the Blue Ridge Mountains of North Carolina. It is currently known to grow in only seven locations. Two additional sites have been lost (more)

 

*Liatris ohlingerae 

Liatris ohlingerae (scrub blazing star) is an endemic perennial herb, found only in the sand pine scrub of Polk and Highlands Counties in Central Florida. Its narrow linear leaves help to conserve water in the dry, well-drained sands in which it occurs. In summer and fall, the vivid rose-purple (more)

 

*Liatris provincialis 

Liatris provincialis, or Godfrey's blazing star, is a perennial herb with beautiful bright purple flowers. The narrow flower spikes, which open from late August to mid-September, can be 6 - 12 inches long. The individual flower heads have very short or no stalks, and spread at right angles to the (more)

 

*Liatris tenuis 

Perennial from globose rootstock; stems solitary or few, unbranched, 1-2 feet tall. Flower heads in a loose spike-like raceme 3-5 inches long, 0.04-0.4 inches between flower heads. Flowers lavender to purple June to September. (more)

 

*Lilaeopsis schaffneriana var. recurva 

Lilaeopsis schaffneriana var. recurva is a herbaceous semi-aquatic perennial growing in marshy wetlands in Arizona (Affolter 1985, Hendrickson and Minckley 1984, Falk and Warren 1994). This species rhizomes creep along streambeds and form dense mats (Affolter 1985). Tiny 3-10 flowered umbels grow (more)

 

*Lilium grayi 

Gray’s lily is a delicate lily of the North Carolina, Tennessee, and Virginia mountains. It is characterized by having purple-spotted orange-red drooping bell-like flowers in mid June-July. Although Gray’s lily generally grows to 2-3’, it can grow up to heights of 8’ (Smith 1998). It is a narrow (more)

 

*Lilium occidentale 

Few wildflowers can rival the beauty and grace of the western lily. If you are fortunate enough to spot one growing in a coastal bog, stop and admire the flowers…but please admire from a distance. With a flower as beautiful as the western lily's, it isn't surprising that horticultural collecting (more)

 

*Lilium pardalinum ssp. pitkinense 

Only three populations of this beautiful lily have ever been discovered. The Fish and Wildlife Service listed the lily as Endangered in 1997, however it is afforded no legal protection as all three populations are on privately owned land. Listing under the Endangered Species Act (ESA) provides no (more)

 

*Lilium parryi 

The lemon lily is a bulbous herbaceous perennial that produces showy, fragrant yellow flowers during the months of July to August. These flower are large, with red spots in their corolla throats. In California, populations numbering in the thousands are found in high-elevation meadows and smaller (more)

 
*Lilium pyrophilum 

 

*Limnanthes floccosa ssp. bellingeriana 

In contrast to some of its showier relatives, such as the outbreeding Limnanthes alba, which form spectacular carpets of creamy white flowers in California's Central Valley in May and June, wooly meadowfoam (L. floccosa ssp. bellingeriana) has a more subtle beauty. The plants are small in stature, (more)

 

*Limnanthes vinculans 

Limnanthes vinculans is an annual from the false mermaid family. It is named so for living in the vernal pool systems of Cotati Valley in Sonoma County, California. This annual produces white flowers in the spring. It was added to the endangered species list in 1991 (USFWS 1992).

Vernal
(more)

 

*Lindera melissifolia 

Pondberry is a pretty, medium sized shrub described by Steyermark (1963) as one of the rarest shrubs in the U.S. The plant flowers in early spring, before leafing out, and produces beautiful bright red fruits in late summer. Pondberry leaves are aromatic and have a strong lemon-sassafras aroma (more)

 

*Lipochaeta lobata var. leptophylla 

Twenty species belong to the genus Lipochaeta, all of which are endemic to Hawai’i. Eight of these twenty species are federally endangered, and another five are species of concern. This particular species is considered a coastal species, and is also the only member of its genus with four parted (more)

 

*Lipochaeta micrantha 

Lipochaeta micrantha var. micrantha is a member of the aster family. It is a woody perennial herb with somewhat triangular and hairy leaves. The flower heads are in clusters of 2 or 3, often purple near the base and along the midrib. Historically, Lipochaeta micrantha var. micrantha was found on (more)

 

*Lipochaeta waimeaensis 

The one known population of Lipochaeta waimeaensis, or nehe, is rapidly declining. In 2000, less that one hundred individuals were recorded (USFWS 2000) and in 2001, less than 50 individuals were located (USFWS 2001). Little is known about the life history of L. waimeaensis. Flowering cycles, (more)

 

*Lithophragma maximum 

Lithophragma maximum is a perennial herb that grows on the moist- northern facing, canyon slopes of San Clemente Island. Plants consist of three lobed leaflets on slender stalks that produce pinkish-white flowers (Hickman 1993). It is threatened by feral goats and pigs and ranching activities that (more)

 

*Lobelia boykinii 

Boykin's lobelia is a semi-aquatic perennial herb that grows to 3 feet in swamps and cypress ponds from the coastal plain of Delaware to Florida (Gleason and Cronquist 1991). The stem is hollow, 40-85 cm. tall and has few if any branches. The lower portion is often immersed in water, at least (more)

 

*Lobelia niihauensis 

low-branched (more)

 

*Lomariopsis kunzeana 

Stem long-creeping, scaly. Leaves dark green, 10-60 cm long, the petiole 3-12 cm long, grooved on the upper side, narrowly winged, scaly at the base and pubescent, the blade oblanceolate, 9-32 cm long, 2-6 cm wide, the pinnae few to many, the terminal pinna like the lateral ones, the larger ones (more)

 

*Lomatium bradshawii 

Lomatium bradshawii was once common, inhabiting the extensive native prairies of the Willamette Valley, creating carpets of sulfur-yellow in the spring. Like many other prairie species, Bradshaw's lomatium has been adversely affected by the extensive conversion of its habitat to agricultural and (more)

 

*Lomatium cookii 

This usually inconspicuous member of the parsley family, with green feathery leaves, is easily spotted when in flower. Although it occurs near well-populated areas, it wasn't discovered until about 20 years ago during a search for another rare plant, the large-flowered wooly meadowfoam (more)

 

*Lomatium erythrocarpum 

Few people have ever seen this diminutive plant that grows high in the Blue Mountains of Eastern Oregon. Lomatium erythrocarpum, with its dull olive-green leaves is easily overlooked except when in flower or fruit (Meinke 1987). The small clusters of flowers are mostly white or purplish, with (more)

 

*Lomatium greenmanii 

Few people have ever seen this diminutive plant that grows high in the Blue Mountains of Eastern Oregon. Lomatium erythrocarpum, with its dull olive-green leaves is easily overlooked except when in flower or fruit (Meinke 1987). The small clusters of flowers are mostly white or purplish, with (more)

 

*Lomatium latilobum 

Canyonlands biscuitroot, Lomatium latilobum, is found on the steep rocky talus created by collapse of the magnificent red sandstone cliffs and in fissures on slickrock. As such, the restricted acessibility of its habitat appears to be protecting this species from extinction (Spackman (more)

 

*Lotus argophyllus var. adsurgens 

Lotus argophyllus var. adsurgens, a shrubby perennial with silvery leaves and yellow-orange flowers, is endemic to San Clemente Island, part of the Channel Islands, California. The Island's recent history of intense grazing has eliminated much of the natural vegetation. Currently, Lotus argophyllus (more)

 

*Lotus dendroideus ssp. traskiae 

Lotus dendroideus var. traskiae is a perennial bush bearing silky branches dotted with yellow or red flowers. This legume is endemic to San Clemente Island, part of the Channel Islands, California. It grows on open, grassy slopes and hillsides. The Island's long history of herbviory has severely (more)

 
*Ludwigia ravenii 

 

*Lupinus aridorum 

Scrub lupine is a woody perennial herb, and is the only upright, pink-flowering lupine in Florida. On stems that can reach 1 m in height are 4-7 cm long leaves that are pointed at the top and rounded at the base. Both leaves and stems are covered by thousands of tiny silver hairs. In bloom (more)

 

*Lupinus biddlei 

This lupine found in eastern Oregon is a treat for the eyes. Its large, palmately-compound, hairy leaves are a vibrant green. These are set off by a tall spike of white flowers. The seeds, about the size of a lentil or slightly larger, range in color from light peach to a beautiful (more)

 

*Lupinus crassus 

Lupinus crassus, or Paradise lupine, is a large herbaceous perennial and member of the Pea Family. It was first collected in 1914 (Payson 1915). The leaves are succulent, appressed puberulent to glabrate. The caudex is branched, forming a dense mat from which arise many decumbent stems. In May the (more)

 

*Lupinus nipomensis 

The total number of known plants has varied from between 100 and approximately 1,800 plants per year, depending on winter rainfall. Plants are distributed as a series of small colonies on the Guadalupe Dunes near the southwest edge of Nipomo Mesa in San Luis Obispo County, California. The primary (more)

 

*Lygodesmia doloresensis 

Lygodesmia doloresensis was first collected in 1947 by H.D. Harrington of Colorado State University. Spencer Tomb then reexamined the plant as part of his doctoral research on Lygodesmia and discovered that it was an unrecognized species. He named it Lygodesmia doloresensis in 1980.

On
(more)

 

*Lysimachia asperulifolia 

Rough-leaved loosestrife is a perennial herb endemic to the coastal plain and sandhills of North Carolina and South Carolina. It grows to about 24 inches tall, has whorled leaves in 3’s and 4’s, and displays 5-petaled yellow flowers from late May to early June (USFWS 1995). Jean Louis Poiret first (more)

 

*Macbridea alba 

Macbridea alba, or white birds-in-a-nest, is quite conspicuous and unmistakable when in flower from May to July. The brilliant white flowers are clustered at the top of the plant in a short spike with bracts. These flowers give the plant its common name, as they look a bit like bird heads in a (more)

 

*Machaeranthera heterocarpa 

Macbridea alba, or white birds-in-a-nest, is quite conspicuous and unmistakable when in flower from May to July. The brilliant white flowers are clustered at the top of the plant in a short spike with bracts. These flowers give the plant its common name, as they look a bit like bird heads in a (more)

 

*Macroptilium supinum 

Macroptilium supinum, a perennial herb, is found in grass woodlands in Arizona and Mexico (Toolin 1982). This species has an unusual breeding syndrome. Flower and seed production occur both above and below ground. Below ground flowers remain closed and are obligate selfers (Buhrow 1983), not (more)

 

*Magnolia pyramidata 

Magnolia pyramidata, known so for its pyramid shaped crown, is one of the rarest magnolias in North America and has potential for a landscape tree due to its compact crown and beautiful creamy-white flowers. This rare tree first became known in Europe when brought to England by Bartram in 1806 (more)

 

*Mahonia sonnei 

No longer taxonomically distinct from the common Berberis (more)

 

*Malacothamnus clementinus 

Malacothamnus clementinus, an evergreen shrub, is a member of the mallow family (Malvaceae). It has numerous ascending branches with large, hairy lobed leaves and produces inflorescences of clustered, pink flowers. M. clementinus is found on sedimentary rock walls and ridges of San Clemente Island, (more)

 

*Malacothamnus fasciculatus var. nesioticus 

Malacothamnus fasciculatus var. nesioticus is a small woody shrub in the mallow family (Malvaceae) that can grow up to two meters in height (USFWS 1997a). The shrub's slender branches are covered with star-shaped hairs and are dotted with small rose colored flowers (USFWS 1995). Malacothamnus (more)

 

*Mammillaria thornberi 

Mamillaria thornberi is a small, clumping columnar cactus with a soft body and numerous tubercules without dorsal grooves (as in Coryphantha). The stems are approximately 15 cm high, and ca 2 cm in diameter. Each tubercule has 10-20 straw-colored radial spines, and a single darker large hooked (more)

 

*Manfreda longiflora 

Manfreda or Runyon's huaco is a small fleshy plant that looks a lot like an aloe. Its leaves have interesting purplish-brown markings. Also called Tuberose because of its fragrant white to pink flowers which bloom on a flower stalk that sometimes reaches a height of 30 inches. The Mexican people (more)

 

*Manihot walkerae 

Manihot walkerae is an endangered plant in South Texas and parts of Mexico (USFWS 1993). It is related to other Manihot species which are grown in Third World countries in order to provide cassava, an important source of starch for millions of people. The roots must first be boiled in order to (more)

 

*Marshallia grandiflora 

Giant Barbara's button is found along scoured riverbanks and in bogs in the Mid-Atlantic region. It produces frilly pink or lavender tubular flowers with blue anthers in June and July. (PDCNR 2002) This rare species is found in only 11 watersheds in the Appalachians and the Cumberland Plateau, and (more)

 
*Marshallia legrandii 

 

*Marsilea villosa 

Marsilea villosa is a fern found only in the Hawaiian Islands, restricted to areas with irregular flooding regimes. Currently, it is known from 3 populations of O`ahu and 2 population on Moloka`i. Many of the historic populations on O`ahu were destroyed by drainage of ponding areas, habitat (more)

 

*Matelea alabamensis 

The Alabama spiny-pod is a climbing or trailing deciduous perennial vine. Each plant produces an aerial stem (1-2 m tall) from an underground rhizome. Leaves are opposite, and can be up to 15 cm long. Small clusters of flowers are borne in the leaf axils on the upper stem. The flower is 15-23 (more)

 

*Mentzelia densa 

Mentzelia densa forms a dense ball up to a meter tall of prickly leaves. These prickly leaves look like miniature Chinese pagodas and easily catch onto clothing and fur. Flowers appear mid-summer and are sunburst-like. The fruit is an oblong dry capsule which is believed to be dispersed by (more)

 

*Mentzelia leucophylla 

Mentzelia leucophylla is an endemic species found on alkaline soil in arroyos, canyons washes, and near spring areas at Ash Meadows National Wildlife Refuge.

A biennial herb, which grows on highly alkaline soils in ash Meadows Wildlife Refuge. This genus has white stems, leaves
(more)

 

*Mentzelia mollis 

The last extensive search for Mentzelia mollis (Smithman 1989) yielded good news: botanists found high population numbers. However, because it is an annual, it is susceptible to dramatic population fluctuations. For instance, the spring of 2001 was extremely dry and few, if any seedlings emerged (more)

 

*Mentzelia packardiae 

Packard's mentzelia makes its way in the harsh, dry, desolate areas of eastern Oregon and northern Nevada. Each spring, seeds germinate in otherwise almost completely barren, dry, ashy soils that have extremely high levels of potassium. Harsh conditions for any plant; but Mentzelia packardiae is (more)

 

*Mentzelia tiehmii 

Mentzelia tiehmii is endemic to Nevada and co-occurs with Frasera gypsicola on gypsum spring mounds in the White River Valley. It is a multi-stemmed sub-shrub that originates from a woody taproot and gets up to one foot tall. Herbage is densely pubescent, stems are white, and the flowers are (more)

 

*Mespilus canescens 

Stern's medlar was first described as a species in 1990 and represents a new generic record for the North American Flora. The closest relative of M. canescens is Mespilus germanica, a species native to Europe and Asia Minor. Together, these species comprise the whole of the genus (more)

 

*Mimulus eastwoodiae 

Mimulus eastwoodiae is a Colorado Plateau endemic, growing in special areas that make it too vulnerable to collectors and sight-seers. New plants are produced from stolons (runners) so that large areas are sometimes covered in M. eastwoodiae plants. Flowers are about an inch long, scarlet to (more)

 

*Mimulus glabratus var. michiganensis 

This plant is a mat-forming, semi-aquatic perennial. The stems can reach 40 cm or more in length and usually trail along the ground, rooting at the leaf nodes, and forming dense mats. The evenly distributed, coarsely toothed leaves are opposite each other along the stems. The bright yellow (more)

 

*Mimulus ringens var. colophilus 

Mimulus ringens var. colophilus is a variety of monkeyflower with a highly restricted distribution from Maine to Quebec. It grows only in freshwater wetlands, usually tidal areas with fluctuating water levels. As a possible adaptation to its specialized habitat, the plant has a compact (more)

 

*Mimulus shevockii 

Mimulus shevockii (Kelson Creek monkeyflower) is a member of the lopseed family (Phrymaceae). It is an annual herb that is only known from within the Kern River drainage in the southern sierra Nevada of Kern County, California.
Mimulus shevockii blooms from March to May and fruits from April
(more)

 

*Minuartia cumberlandensis 

Minuartia cumberlandensis is a schizoendemic that grows exclusively behind the dripline in sandstone rockhouse shelters (cave-like recesses beneath cliff overhangs) on the Cumberland Plateau (Kentucky and Tennessee). Because this unique habitat is sheltered from abrupt climate change, this species (more)

 
*Minuartia marcescens 

 

*Mirabilis macfarlanei 

This showy plant is quite something if you encounter it in the dry areas of Eastern Oregon and Western Idaho. Often growing on dry, steep slopes high above the river, this four-o'clock, with bright magenta flowers and purplish stems, stands out on the brownish hillsides.

Mirabilis
(more)

 

*Mirabilis rotundifolia 

The Arkansas River Valley of Colorado supports many unusual flora. Although some taxa are abundant several are narrowly restricted to the area of carbonate shales of the Niobrara Formation (Von Bargen 1997). Oxybaphus rotundifolius is one of the narrow endemics whose distribution is limited to (more)

 

*Mitracarpus maxwelliae 

Mitracarpus maxwelliae is a low growing, densely branched, mound-shaped shrub that is endemic to a sub-tropical dry forest in southwestern Puerto Rico (USFWS 1994, USFWS 1998). M. maxwelliae's limited distribution in tandem with human threats and environmental stochasticity make it highly (more)

 

*Mitracarpus polycladus 

Mitracarpus polycladus is a suffrutescent perennial with branching stems near its base that spread out to produce clusters of white flowers (USFWS 1994, USFWS 1998). M. polycladus can be found growing in the crevices of coastal in a sub-tropical dry forest in southwestern Puerto Rico and also on (more)

 

*Monardella douglasii ssp. venosa 

Veiny monardella is an annual herb to 0.3 meters tall with purple flowers from May to July. It's known only from six populations in Butte County, in northern California. It was thought to be extinct until its rediscovery in 1992, having been last documented in 1935 in Tuolumne County. The area (more)

 

*Muhlenbergia torreyana 

This range of the New Jersey muhly has significantly declined over the last century, but it is still found in four states, one of which is New Jersey, where the species is locally abundant in the Pine Barrens. (NatureServe 2001).

A true grass, M. torreyana produces a plume of purple
(more)

 

*Munroidendron racemosum 

Munroidendron is an endangered, monotypic genus that is endemic to Hawai’i and a member of the ginseng family (Araliaceae). The only member of this genus is Munroidendron racemosum, a small tree (25 ft. tall) with a straight gray trunk and spreading branches. Leaves are 12 inches long and made up (more)

 

*Napaea dioica 

This mallow species produces attractive white flowers in June and July (NatureServe Explorer 2002) and is cultivated for ornamental purposes by a number of nurseries. After the last glaciation, N. dioica expanded its range via riparian corridors (Botany2001 website 2002). Its range has become (more)

 

*Narthecium americanum 

This perennial lily, growing up to half a meter tall, graces pine barrens bogs with its beautiful yellow flowers in June and July. The species' stronghold is in New Jersey, although a few far-flung populations are reported from the Carolinas and Delaware. A few dozen small populations are (more)

 

*Navarretia fossalis 

Navarretia fossalis is an annual herb found in vernal pools and other shallow freshwater depressions in northwestern Baja, California (USFW 1994). The whitish lavender flowers are arranged in flattened clusters, bloom from April to June and produce two celled capsules of reddish brown seeds (more)

 

 

*Nitrophila mohavensis 

This member of the Chenopodiaceae family occupies the most localized habitat of all plant species endemic to Ash Meadows. Its habitats are limited to highly alkaline, moist, salt-encrusted clay soils. It is the only species to occupy these specific areas, and will not reestablish where the salty (more)

 

*Nolina brittoniana 

Nolina brittoniana is a perennial herb that is a member of the Agavaceae family. It has the typical agave-like long, stiff leaves in a grass-like clump that rise from a bulbous stem. The youngest leaves are erect while the older leaves (up to 6 feet long, 0.5 inch wide) spread on the ground. The (more)

 

*Nolina interrata 

Nolina interrata is a large succulent perennial that forms rosettes of long, flat leaves and tall flowering stalks. The lightly colored flowers are dioecious and produce reddish brown seeds (Hickman 1993).

This endangered plant is found in the chaparral region of south central San Diego
(more)

 

*Nothocestrum breviflorum 

These stout trees (10-12 m) were called by the famous early 20th century botanist Joseph Rock "the most ugly trees which the Hawaiian Islands possess (Rock 1974: 421)." The trunk is knobby, and the branches sometimes bare altogether, as the tree is seasonally deciduous. The thick, papery leaves, (more)

 

 

*Nototrichium divaricatum 

There are three Nototrichium species endemic to Hawai’i, one is endangered, one is apparently secure, and N. divaricatum is listed as a species of concern. This particular species, N. divaricatum, is a shrub that can grow up to 50 centimeters (20 in) tall. The leaves of N. divaricatum are (more)

 

*Oenothera californica ssp. eurekensis 

Oenothera californica is a perennial herb that produces white flowers from April to June. These flowers turn red as they age. The Eureka Dunes evening-primrose is found only in the southern portion of Eureka Valley Sand Dunes system in Indigo County, California.

Since the 1960's, the
(more)

 

*Oenothera deltoides ssp. howellii 

In 1984 a humpback whale beached itself on the dunes in the Antioch Dunes National Wildlife Refuge. Thousands of people came to see the animal, using the dunes to get the best view and, unfortunately, killing a number of endangered plant species growing there by trampling them to death. One of the (more)

 

*Oenothera pilosella ssp. sessilis 

Oenothera pilosella subsp. sessilis is beautiful native perennial herb with showy yellow flowers that bloom between May-June. Restricted primarily to remnant tallgrass prairies in the lower Mississippi River Valley, this species has declined dramatically in the wild due to conversion of prairie (more)

 

*Oenothera wolfii 

Of all the many ways to be driven to extinction, Wolf's evening primrose is under assault from one of the most insidious and bizarre; its own offspring! We believe that children are a blessing. We believe that genetic diversity and the mixing of genomes is a good thing. In the botanical world, (more)

 

*Oonopsis foliosa var. monocephala 

The high plains of southeastern Colorado is home to the rayless goldenweed, a wildflower that occurs in places where erosion has thinned the mantle of shortgrass prairie. The ecology of this plant may have been linked with the massive bison herds that once thrashed the prairie during their (more)

 

*Opuntia basilaris var. treleasei 

Very little is known about this variety of prickly pear cactus. About a third of the historic occurrences have been extirpated and the remaining populations are highly fragmented. This is due to habitat loss caused by agricultural development in the region in the early 1900's. Continued development (more)

 

*Opuntia triacantha 

Opuntia triacantha is a prickly pear cactus native to the Florida Keys and islands of the Caribbean (Britton and Rose 2000). The stems of this low-growing cactus have strongly-barbed spines, and are flattened and nearly prostrate, with loosely attached joints, giving the impression that is has (more)

 

*Orcuttia californica 

Orcuttia californica is a bright green, aromatic, and densely tufted annual grass. Its pink flowers occur in dense spikes and bloom from April to June (Hickman 1993). This species was once commonly found in the volcanic terrace and vernal pool system in Los Angeles, Riverside and San Diego (more)

 

*Oxypolis canbyi 

Canby’s dropwort is a perennial aromatic herb with quill-like leaves, slender stems and reproduces by strong, fleshy rhizomes. It is found in the Coastal Plain regions of Delaware, Maryland, North Carolina, South Carolina and Georgia in pond cypress savannas, shallows of ponds, sloughs, and wet (more)

 

*Oxytropis campestris var. chartacea 

O. campestris var. chartacea is one of the famous locoweeds known for causing cattle to behave in unusual ways. It is endemic to central Wisconsin. This species is extremely shade intolerant and suffers from habitat destruction and succession of the lake shores it inhabits. It relies on changing (more)

 

*Oxytropis campestris var. johannensis 

Oxytropis campestris var. johannensis is a river-side legume endemic to Maine and eastern Canada. Its deep taproot and compact architecture help it withstand the frequent flooding and ice scour common along wild, rocky northern rivers, and its populations shift along the shoreline when disturbance (more)

 

*Panicum hirstii 

Panicum hirstii is a stiffly erect panic grass that grows 20 - 60 cm (8 - 23 in) tall. The taxon inhabits sandy pine woods and pond shores of the coastal plain barrens of New Jersey, Delaware, and North Carolina. It is also found in limestone depression ponds and shallow Cypress ponds of Georgia. (more)

 

*Parnassia caroliniana 

Parnassia caroliniana is a moisture-loving species that occurs in the Coastal Plain and Sandhills of the southeast. It grows in fire-maintained, wet savannas and in ecotonal areas between pine uplands and seepage slopes or streamhead pocosins. The solitary white flowers of Carolina (more)

 

*Paronychia chartacea 

There are two geographically isolated subspecies of Paronychia chartacea (ssp. chartacea and ssp. minima). Anderson (1991) describes the differences between these two subspecies. Both of these subspecies are listed as federally threatened due to habitat loss from agricultural, commercial, (more)

 

*Parthenium alpinum 

The Wyoming feverfew was lost for over 100 years. First collected in 1834 by famed botanical explorer Thomas Nuttall somewhere along the route that would later become the Oregon Trail, it was not seen again until 1947, when it was rediscovered in central Wyoming. Inhabiting rocky, windswept places (more)

 

*Paxistima canbyi 

Paxistima canbyi is a low growing evergreen shrub that reaches 1-2 dm in height. It produces small green flowers with four sepals and four petals from March to April. The branches of this species spread out along the ground, sprouting wherever conditions are right. This leads to the formation of (more)

 

*Pedicularis furbishiae 

Pedicularis furbishiae is a narrow endemic, found only along 225 km of the pristine St. John River system of Maine and adjacent New Brunswick. Kate Furbish, botanist and wildflower artist, discovered the plant in 1880, and it has been intensively studied ever since. One of the first plants to (more)

 

*Pediocactus despainii 

This is the most recently described species in this genus after only being discovered in 1978 by graduate student Kim Despain. It is no surprise that this species was overlooked for so long; it is easy to miss due to its small stature and peculiar habit of receding underground for several months a (more)

 

*Pediocactus knowltonii 

Pediocactus knowltonii L. Benson, Knowlton’s cactus, is a critically imperiled species with a single known viable population in New Mexico and adjacent Colorado. It is a Federally listed species as of 1979.

Pediocactus knowltonii is small, about the size of a penny, with large white
(more)

 

 

*Pediocactus winkleri 

This rare cactus is considered endangered by the World Conservation Union (IUCN) and listed in Appendix I of the Convention on the International Trade in Endangered Species (CITES). In this designation, P. winkleri joins the ranks of other endangered species such as tigers, Asian elephants, (more)

 
*Pediomelum humile 

 

*Peniocereus greggii var. transmontanus 

One of the threats to this species comes from its popularity--this is a plant with a history of religious, medicinal, and ornamental use. Both private and commercial collectors have had a serious impact on the abundance of this species in its natural habitat by digging entire plants up. (more)

 

*Penstemon albomarginatus 

A perennial herb, 1.5-3 dm tall, distinctively pallid in color. The spatula-shaped leaves and the calyx lobes are conspicuously white-margined. Flowers (March-May) are pink-lavender with darker purple (more)

 

*Penstemon barrettiae 

Penstemon barrettiae may be easy to spot when in full bloom, but it is anything but easy to study.

This beautiful penstemon with thick, leathery bluish- to gray- green leaves and long, tubular rose-purple flowers can easily be seen clinging to the cliffs that it calls home. Because of
(more)

 

*Penstemon clutei 

Penstemon clutei is a unique species in a genus of nearly 300 species in North and Central America. Forty six of these 300 species are found in Arizona. (Lehr 1978)

Plants have one to several stems that grow up to 32 inches tall. Leaves are waxy and serrate. Bright pink tubular
(more)

 

*Penstemon debilis 

Penstemon debilis O’Kane and J.L. Anderson, the Parachute beardtongue, is a perennial forb of the Scrophulariaceae family. This species lacks aerial stems, has succulent, glabrous, and glacous leaves, and white to pale lavender flowers that bloom from mid June to mid (more)

 

*Penstemon degeneri 

Penstemon degeneri is one of the rarest and least-known penstemons in Colorado. It was named after its first known collector, Dr. Otto Degener in recognition of his collections and interest in conservation. (Crosswhite 1965) Since then, it has been reported only two more times (Von Bargen (more)

 

*Penstemon fruticiformis ssp. amargosae 

Penstemon fruticiformis ssp. amargosae is a short, shrubby perennial with pale-pink to whitish flowers containing strongly lined lavender nectar guides that signal pollinators to a nectar reward. (See CalFlora (2000) for photos). This Penstemon grows in gravely washes, canyon floors and (more)

 

*Penstemon gibbensii 

Plants in the genus Penstemon are known for their showy floral displays. However, P. gibbensii has very small, inconspicuous flowers. This uncharacteristic trait may be an indication of the environment that P. gibbensii occupies--the dry, cold steppe regions of Colorado and Wyoming on barren shale (more)

 

*Penstemon grahamii 

Graham’s beardtongue (Penstemon grahamii) is a herbaceous perennial. When in flower plants are easily sited. The colors of the flowers are brilliant lavender to pink and the tubular flower is long compared to other penstemon species. The flowers (3-20) are usually tightly arranged around the (more)

 

*Penstemon harringtonii 

Penstemon harringtonii, or Harrington's beardtongue, is a narrowly endemic perennial herb and a member of the Figwort Family. It is 30-70 cm tall; the flowers are large, purple to blue and disposed in loose spikes on the upper half of the stems, blooming in June. This plant is easily recognized by (more)

 

*Penstemon haydenii 

The sandhills region of Nebraska constitutes the largest dune field in the western hemisphere and one of the largest intact grasslands in North America. While most of the dunes are mantled with prairie vegetation, wind erosion opens up areas of bare sand called blowouts. The blowout penstemon (more)

 

*Penstemon penlandii 

Penstemon penlandii, a member of the snapdragon family, can grow up to 10 inches in height. It has 5-15 flowers per stem with purple throats and blue lobes that fade to pink as they age. The only known site for P. penlandii is in Colorado on alkaline shale that weathers into barren clay (more)

 

*Penstemon retrorsus 

Adobe Hills beardtongue is found in north-facing slopes on adobe hills derived from Mancos Formation shale in Montrose and Delta counties. The stems rise erect from a woody rootstock that gives rise to a mat of stems and leaves. The coarse, dense hairs cover the leaves and stems of Penstemon (more)

 

*Penstemon scariosus var. albifluvis 

The White River penstemon is found along the White River that flows westward from the Flat Tops area of Western Colorado until it joins the Green River in Utah. Both the common and scientific name of this species is named after its location (albus, meaning white, and fluvis meaning river). (more)

 

*Penstemon stephensii 

Penstemon stephensii, part of the Snapdragon Family (Scrophulariaceae), is endemic to southeastern California. It can be found in communities such as Creosote Bush Scrub and Pinyon-Juniper woodlands (CalPhotos (more)

 

*Peperomia wheeleri 

Peperomia wheeleri, and evergreen herb, can grow up to one meter in height and produces clusters of small, hermaphroditic flowers that form into spikes 10-15 centimeters in length (USFWS 1986a). P. wheeleri is restricted to the semi-evergreen forests on Culebra Island, a part of Puerto Rico. (more)

 

*Perideridia erythrorhiza 

How can simply changing a species' name help to protect it?

Perideridia erythrorhiza is found on both sides of the Cascade Range in southwestern Oregon. Significant morphological and biological differences between plants at the two locations have led researchers to believe that they
(more)

 

*Phacelia argentea 

Silvery phacelia is the only known Phacelia to grow on coastal sand dunes (Rittenhouse 1995). It grows on the immediate coastal dunes from northern Del Norte County in California to southern Coos County in Oregon. Although this seems like a large distribution (it spans 130 miles), not all of this (more)

 

*Phacelia argillacea 

Clay phacelia is a Federally listed endangered plant. It is found in only one location in the world--Spanish Fork Canyon in Utah. In 1977, only nine plants were known to exist. The main cause attributed to this decline was the construction of a railroad directly through the known population, and (more)

 

*Phacelia formosula 

Phacelia formosula is found only in the erosive sandstone outcrops of the Coalmont Formation in North Park of Jackson County, Colorado. It was first discovered on August 6, 1918 by the Colorado botanist, George Osterhout. Other sites where not identified until 1981. There are less than ten (more)

 

*Phacelia submutica 

Phacelia scopulina (A. Nelson) J.T. Howell var. submutica (J.T. Howell) Halse, the Debeque phacelia, is an annual forb of the Hydrophyllaceae family. It is a candidate for Federal listing and is ranked as Imperiled by NatureServe. It is also known as Phacelia submutica. This species forms a small (more)

 

*Phlox nivalis ssp. texensis 

Once considered extinct, the Texas trailing phlox was rediscovered by Geyata Ajilvsgi of Bryan, Texas in 1972 (Ajilvsgi 1979). This species was eventually federally listed as endangered in 1991 and, since that time, a handful of new populations have been discovered and reintroduction efforts have (more)

 
*Pholisma arenarium 

 

*Pholisma sonorae 

Pholisma sonorae is an obscure, parasitic plant with extremely strange attributes. The plants are gray and mushroom-shaped, and their height depends on the degree to which blowing sand covers the scaly stem (Armstrong 1980a). This succulent stem extends 1-2 m below the sand, and is attached to (more)

 

*Physaria bellii 

A member of the Mustard family, Physaria belli is restricted to limestone and calcareous shales of the Niobrara formation in the northern front range of Colorado. The bright yellow flowers of this plant form a halo around the grayish/green basal rosette of leaves. "Physa" mean bubble, which (more)

 

*Physaria obcordata 

Piceance twinpod, a small herbaceous perennial that is a member of the Mustard Family was first documented in 1982 by two members of the Colorado Natural Heritage Inventory, and eventually named by Reed Rollins (Al-shehbaz 1998). It was named for its distinctive heart-shaped fruits (cordate) that (more)

 

*Physaria pulvinata 

It forms symmetrical mounds of narrow, spotted leaves and in early summer blooms profusely.

(more)

 

*Physaria tuplashensis 

In 1994, the Nature Conservancy of Washington and the US Department of Energy began the Hanford Biodiversity Project. The Hanford Nuclear Site, through which the Columbia River flows in south-central Washington, contains some of the largest remnant areas of ungrazed and undeveloped shrub steppe in (more)

 

*Physostegia correllii 

Correll's false dragonhead is an endangered, water-loving perennial that once occurred in several areas in Texas, Louisiana, and Mexico but is now restricted to two or three sites in Louisiana and one possible site in Travis County, Texas (Poole 2001; Singhurst 2001). Its current status in (more)

 

*Physostegia longisepala 

Erect, rhizomatous perennial to 3 feet tall, stem squarish, with 9-15 nodes below inflorescence; primary rhizome branching to produce one to many elongate horizontal secondary rhizomes. Leaves opposite and simple, lower ones with petioles and upper ones sessile, mostly clasping the stem, 2-5" long, (more)

 

*Pilosocereus robinii 

The keys tree cactus is unlike any other plant in Florida. It is a true tree, with mature individuals possessing differentiated trunks and branches (Avery 1982). Plants can reach as high as 10 m, and may have dozens of spreading branches (Ward 1979), though most of the larger plants have been (more)

 
*Pilosocereus robinii var. robinii 

 

*Pityopsis ruthii 

Ruth's Golden-aster is an herbaceous tufted perennial that has slender stoloniferous rhizomes. Its leaves are numerous, cauline, linear, and silvered with long apressed hairs. The inflorescence is comprised of one to several heads of yellow composite flowers in a cyme. This southeastern Tennessee (more)

 

*Plagiobothrys figuratus ssp. corallicarpus 

Plagiobothrys figuratus is a common and widespread plant found from Vancouver, British Columbia to southwestern Oregon. The more localized Plagiobothrys figuratus ssp. corallicarpus is found at only 18 sites within a small area in the Middle Rogue River Basin and the Jenny Creek watershed in (more)

 

*Plagiobothrys hirtus var. hirtus 

The native wetlands occupied by this species offer a unique combination of intertwining aquatic and terrestrial life. Many native annual plants, including skullcap speedwell (Veronica scutellata), Willamette downingia (Downingia yina), and Douglas' meadow-foam (Limnanthes douglasii), as well as a (more)

 

 

*Plantago cordata 

The heartleaf plantain is a semi-aquatic plant that is found primarily in central and northeastern U.S. and Canada, with disjunct populations occurring in Georgia and possibly Florida. (Bowles and Apfelbaum 1987) This species has declined throughout much of its range, with a number of Midwestern (more)

 

*Plantago princeps var. anomala 

The heartleaf plantain is a semi-aquatic plant that is found primarily in central and northeastern U.S. and Canada, with disjunct populations occurring in Georgia and possibly Florida. (Bowles and Apfelbaum 1987) This species has declined throughout much of its range, with a number of Midwestern (more)

 

*Platanthera holochila 

Platanthera holochila is one of only three species of orchids endemic to Hawai`i. It is an erect herb whose long stems arise from underground tubers. Its pale green leaves are egg-shaped and greenish-yellow flowers occur on open spikes. Historically, it was known from the Alakai Swamp and (more)

 

*Platanthera leucophaea 

P. leucophaea is one of the largest and showiest of the native North American orchids. It is one of at least 200 North American orchid species, and is currently listed as Federally Threatened. This species has declined in the United States by more than 70 percent from original county records. (more)

 

*Platanthera praeclara 

The fate of the western prairie fringed orchid is tied to that of the tallgrass prairie. This elegant wildflower, with its clusters of showy white flowers, was once found in grassy swales and meadows from Manitoba south into Oklahoma. Now, with the tallgrass prairie reduced to less than two-percent (more)

 

*Pleomele hawaiiensis 

This species is a member of the agave family, and historically had many uses by native Hawaiians. Its large yellow flowers were used for leis, wood was used for carved images and hula offerings by native Hawaiians. Currently, these plants are experiencing poor reproductive success in the wild, (more)

 

*Pleuropogon oregonus 

The very existence of Oregon semaphore grass has been a recurring question over the past 100 years. In 1886, William C. Cusick first collected this grass in what was once called Hog Valley in northeastern Oregon, and another collection was made in Union, Oregon in 1901. It was not collected again (more)

 

*Poa atropurpurea 

Poa atropurpurea (San Bernardino Bluegrass) is a member of the grass family (Poaceae) that is dioecious (separate male and female plants), growing as a tufted perennial with creeping rhizomes (Soreng 1993). This species is endemic to southern California and occurs in the Big Bear region of the San (more)

 

*Poa mannii 

There are three endangered Poa species endemic to Hawai’i (U.S. Fish and Wildlife Service [USFWS] 2001), and all are found only on the island of Kauai. P. mannii, a member of the grass family (Poaceae) is a perennial grass with short rhizomes (underground stems) and erect, tufted culms (hollow or (more)

 

*Poa paludigena 

This species is a small, often overlooked, easily misidentified grass. It frequents wet, cool habitats where it associates with alders or other shrubs and small herbaceous plants, sometimes growing on mossy hummocks, until larger species move in and increase shade over the area. It has no (more)

 

*Pogogyne clareana 

Santa Lucia mint is a delicate, strongly scented annual up to 40 cm tall with dense terminal clusters of deep pink flowers 10-15 mm long. It occurs along small ephemeral streams and in vernal pools. It was listed as Endangered by the State of California in 1979, based on reports of a few thousand (more)

 

*Pogogyne nudiuscula 

Pogogyne nudiuscula is an annual herb in the mint family (Lamiaceae) that is endemic to the vernal pool systems in southwestern California. Its purple tinged flowers bloom after the rainy season when pools begin to dry down, from May through early July (USFWS 1998). This species is currently found (more)

 

*Polemonium occidentale var. lacustre 

Polemonium occidentale var. lacustre is the extremely rare Midwestern variety of a more common western species that is found in Minnesota and Wisconsin. The name "lacustre" refers to the fact that this subspecies is found only in wetland habitat. This single stemmed phlox produces bright violet (more)

 

*Polemonium pectinatum 

According to the Endangered Species Act, rare plants found on private land are not required to receive specialized protection. Landowners are not required preserve an endangered plant's habitat. This is cause of concern for Polemonium pectinatum, an herbaceous perennial endemic to eastern (more)

 

*Polemonium van-bruntiae 

Polemonium van-bruntiae is an herbaceous perennial plant. It has distinctive compound leaves that resemble ladder, which give the plant its common name of Jacob's ladder. Although this attractive plant is sometimes cultivated and sold to gardening enthusiasts, it is rare in the wild throughout (more)

 

*Polygala cowellii 

This is a tree that grows from 30 to 40 feet in height. Very little is known about this (more)

 

*Polygala lewtonii 

P. lewtonii is a short-lived (5 to 10 year) perennial herb with one to several annual stems that grow up to 20 centimeters tall. Stems are spreading, upward-curving, or erect, and often branched. The narrow, succulent sessile leaves are 0.5 inches long, wider above the middle, and overlapping (more)

 

*Polygala smallii 

long-lived ephemeral erect biennial (more)

 

*Polygonella basiramia 

This short-lived, herbaceous perennial is endemic to the central ridges of the Florida peninsula. It is found in sand pine scrub habitat, and requires periodic disturbance, such as fire, to maintain this habitat in the correct conditions for the survival and persistence of the species. (more)

 

*Polygonella macrophylla 

Polygonella macrophylla, or large-leaved jointweed, is a small slender shrub found in the deep white sands of the Florida Panhandle, on sand pine-oak scrub ridges. The development of this coastal habitat is a major contributor to the decline of the species.

Large-leaved jointweed has
(more)

 

*Polymnia cossatotensis 

This species was discovered in 1988 in the Ouachita Mountains, Arkansas. All five known populations are within the Ouachita National Forest in an area less than 18km from one another. Two of the populations are quite small, and three are large. The larger populations seem to have remained stable (more)

 

*Potentilla basaltica 

Potentilla basaltica is native to California and Nevada. It is known from only four occurrences, two in California and two in Nevada. It is listed as a Federal Candidate and the Nevada Native Plant Society lists it as threatened. The stems of the plant become purple with age, the leaves form a (more)

 

*Potentilla robbinsiana 

Potentilla robbinsiana is a long-lived, dwarf, alpine perennial. The species is endemic to the White Mountains of New Hampshire, and the main population of several thousand individuals clings to one of the most rugged areas of Mount Washington. Although each tiny plant only covers an area 2-6 cm (more)

 

*Potentilla rupincola 

Potentilla rupincola is a low-growing perennial. It is usually caespitose (with a cushion plant growth form) (Child personal communication 2002, Scully personal communication 2002), but plants in sheltered sites may be taller and more erect, up to three dm tall (as described in Osterhout (1899) and (more)

 
*Prenanthes boottii 

 

*Primula maguirei 

The Maguire primrose is a perennial herbaceous plant with bright-green, spatula-shaped leaves. From mid-April to mid-May, this beauty produces showy, reddish lavender flowers approximately 1 inch across that are borne on graceful stems up to 6 inches high. Unfortunately, this species is very rare (more)

 

*Pritchardia affinis 

A fine-looking, long-lived palm at 10-25 m (33-82 ft) tall, P. affinis is often used as a landscape specimen on the west side of Hawai'i Island. It is one of 19 native species of the fan palm genus Pritchardia, distinguished by undulating, pale green and often yellowing blades and almost round (more)

 

 

*Pritchardia munroi 

Pritchardia munroi is a member of the palm family (Araecaceae). It is a tree up to 4 to 5 meters tall with drooping leaves that are deeply divided into segments. It was discovered in 1920 by Joseph F. Rock on the island of Moloka`i in Hawai`i and named it after James Munro, manager of Moloka`i (more)

 

 

 

*Pritchardia viscosa 

There are twenty three species of Pritchardia endemic to Hawaii, all are threatened with extinction. This particular species, Pritchardia viscosa, is threatened with extinction for a number of reasons, not the least of them is the fact that there is only one remaining population with only four (more)

 

*Proboscidea sabulosa 

Proboscidea sabulosa is an annual, hairy- and sticky-leaved herb with rounded leaves. Plants are about 0.4 m across and high, with rounded dark green leaves that are very glandular and somewhat pungent. The creamy white, purple spotted flowers grow in clusters under leaves. The woody fruits (more)

 

*Prunus alleghaniensis 

Prunus alleghaniensis is a rare small tree that can grow as a shrub and sometimes form extensive thickets. Its height is up to 4-5 m; young shoots are pubescent, becoming lustrous red during the first winter, then darkening to nearly black. It may grow either unarmed or armed with spinescent (more)

 

*Prunus alleghaniensis var. davisii 

This variety is endemic to the Lower Peninsula of Michigan. It flowers rather early in April producing white flowers with stamen filaments that turn dark pink as the flower ages. Both birds and mammals feed on the small plum fruit and disperse the seeds in mid to late summer. The pink stamens and (more)

 

*Prunus geniculata 

Scrub plum (Prunus geniculata) is a woody shrub restricted to xeric upland habitats on the Lake Wales Ridge of Central Florida. It is a member of the rose family (the Rosaceae) which includes peaches, cherries, apricots, almonds and...roses. Scrub plum is very drought tolerant, with small leaves (more)

 

*Prunus maritima var. gravesii 

Originally found by Small in 1897, this variety no longer exists in the wild. It differs from the common beach plum (P. maritima) in that it has round instead of elliptical leaves. It turns out that this plant is a mutant derivative that depends on P. gravesii for pollen. Some consider it (more)

 

*Pseudophoenix sargentii 

tree to 6 meters (more)

 

*Ptilagrostis porteri 

Porter's false needlegrass, a small perennial bunchgrass that is a member of the Poaceae (Grass) Family can grow 20-35 cm tall. The fine and very narrow leaves are mostly basal. The one-flowered spikelets resemble the needlegrasses. The awn, a special part of the grass flower, is plumose along its (more)

 

*Ptilimnium nodosum 

Harperella grows along rocky shoals of clear swift-flowing streams, and requires a very narrow range of hydrologic conditions in order to survive. The water depth can't be too high nor too low and the water quality must be good. This has made the species highly vulnerable to any seemingly minor (more)

 

*Puccinellia howellii 

A small cluster of mineral springs in Shasta County, California is the only place that the perennial bunchgrass Puccinellia howellii has ever been found. The total spring area is only 1.2 acres (about 52,000-sq. ft.), and the limited habitat makes this species particularly vulnerable to (more)

 

*Purshia subintegra 

Arizona cliffrose, Purshia subintegra (Kearney) Henrickson is a xeric rosaceaeous evergreen shrub with pale yellow flowers and entire leaves that lack glands. Usually less than 2 m tall, it is closely related to Purshia stansburiana, a widespread species that has lobed leaves with glands and (more)

 

*Pyxidanthera barbulata 

Pyxidanthera barbulata is a diminutive, creeping evergreen sub-shrub that forms dense mats sprinkled with delicate white-pink flowers. Its prostrate growth form and crowded tiny leaves allow the plant to conserve water in the very xeric habitats in which it occurs. Its habitat includes the (more)

 

*Quercus hinckleyi 

This unique oak is an attractive evergreen shrub forms thickets about 4 feet tall where it occurs. Its grayish-green, holly-like leaves give it a smoky appearance from a distance. It is found growing in the Chihuahuan desert on dry slopes at a 4500 foot elevation (Correll and Johnston 1996). (more)

 

*Ranunculus aestivalis 

Autumn buttercup is so named because it flowers late in the season. It was first collected in 1894 near Panguitch, Utah. It was relocated in 1948, but L. Benson, the botanist who rediscovered the population, recommended that the plants shouldn't be collected because the population didn't appear (more)

 

*Ranunculus reconditus 

First of all, there are very few populations of Ranunculus reconditus. Secondly, although the species is listed as Endangered by the State of Oregon and Threatened by the State of Washington, only one piece of land is officially protected due to where the populations are located. Populations on (more)

 

*Rayjacksonia aurea 

The Houston camphor daisy's range spans only Galveston and Harris counties. It is a tap-rooted annual member in the sunflower family with attractive golden-yellow camphor-scented flowers in October and November. Although it can grow up to waist high in cultivation, in its characteristically harsh (more)

 

*Remya kauaiensis 

R. kauaiensis (Asteraceae) is one of three species of a genus endemic to the Hawaiian Islands. It was considered extinct for over 30 years, until 4 populations were discovered starting in 1983. In 2000, 14 populations with a total of approximately 80 plants of R. kauaiensis were recorded (U.S. (more)

 

*Rhexia aristosa 

Rhexia aristosa is an erect, herbaceous perennial that grows to 1 meter tall. It has opposite, linear, lanceolate leaves and large purple flowers that are arranged in a cyme. The Awned meadowbeauty is found in a variety of wet habitats in the Coastal Plain from New Jersey to Alabama. More and more (more)

 

*Rhododendron austrinum 

This species is an incredibly popular garden plant. It is known for its pleasant fragrance and its brightly colored flowers which range from cream to orange with red striping. It is widely available at plant nurseries in the south and at online stores. Not much is known about this plant in the (more)

 

*Rhododendron prunifolium 

Rhododendron prunifolium is one of the showiest native azaleas and can grow up to 18 ft in height (Wilson and Rheder 1921, Cox 1990, Dirr 1998). The clustered, brightly crimson-colored flowers bloom from mid-July to mid-August, and occasionally in September (Foote and Jones 1994) . The flowers' (more)

 

*Rhododendron vaseyi 

Rhododendron vaseyi is a deciduous, upright narrow shrub that can grow to 5 meters in height with appealing erect branches (Wilson and Rehder 1921, Cox 1990) Its root system is compact and shallow. Scentless, pinkish white flowers begin blooming in April and are thought to attract hummingbirds (more)

 

*Rhus kearneyi 

Rhus kearneyi plants are large showy, evergreen shrubs that grow up to three meters in height. The dioecious flowers grow in creamy white clusters and bloom in March. Petioles and young twigs are a striking reddish color. Many species of Rhus can be found in small numbers in the canyons of northern (more)

 

*Rhus michauxii 

Half of the known historical populations of Rhus michauxii have been extirpated in the last century. The few remaining populations are in a precarious position for a number of reasons, perhaps the most important of these being the species’ low reproductive capacity and its dependence on (more)

 

*Rhynchospora knieskernii 

Rhynchospora kneiskernii is a grass-like plant of the Sedge family that grows only in the Pinelands of New Jersey. A short-lived perennial, the plant inhabits disturbed, open, early-successional wet areas in gravel and clay pits, power-line and railroad rights-of-way, recent burns, muddy swales, (more)

 

*Rorippa gambelii 

Once found from San Luis Obispo County south to San Bernardino County, California, and in central Mexico, Gambel’s watercress today is known from only three localities in the United States, and its numbers have dwindled to perhaps less than 300 individuals. Known from about 8 occurrences in the (more)

 

*Rorippa subumbellata 

Lake Tahoe is a popular vacation destination for many Americans. Perhaps, too popular. This hot-spot for boaters and sunbathers is the only naturally occurring site of the Lake Tahoe yellowcress. Rorippa subumbellata inhabits a seven-foot "tidal" zone between the low and high water lines of Lake (more)

 

*Rudbeckia scabrifolia 

Bog Coneflower is an erect perennial to six feet tall, branched above. Leaves at the base and on the stem, dark green, leathery and lustrous; basal to 14 inches. Flower heads 2-15 in a branched panicle, typical composite with the center green to brown and rays 10-15 pale yellow and drooping, 3/4 to (more)

 

*Rumex orthoneurus 

This species is a long-lived herbaceous perennial plant. If can grow to a height of 2 meters (6.6 ft) and produces oblong, semi-succulent basal leaves that are large (up to 45 cm (18 in) long and 18 cm (7 in) wide). Flowers appear from late July to mid-August on plants that are over one or two (more)

 

*Sabal causiarum 

Sabal causiarum, or hat palm, is endemic to southwestern Puerto Rico. This species was once widespread on the island, and was often used to make hats and baskets (Tucker 1927). This palm can be distinguished from other palms because it grows up to 50 feet in height, rising from a massive, smooth (more)

 

*Sabatia kennedyana 

Sabatia kennedyana is a perennial, herbaceous plant bearing gorgeous, pink, daisy-like flowers on tall stems. It forms colonies along the shores of coastal plain ponds from Nova Scotia south to South Carolina. The population densities and reproduction of this species are tightly tied to (more)

 

*Sagittaria fasciculata 

Endemic to two counties of the Carolinas, this aquatic herb has a severely threatened habitat. The mountain bogs in which Sagittaria fasciculata occurs have been drained for residential development and pasture. In the few remaining suitable sites, the population growth of nearby cities presents (more)

 

*Salix arizonica 

Arizona willow is a small shrub that forms prostrate mats, single shrubs, or large hedges or thickets ranging from several centimeters to 3 m tall, but typically less than 8 dm tall. Its shiny oval leaves have finely serrate margins and are gland-tipped. Young stems of this species are bright red, (more)

 

*Salvia pentstemonoides 

Big red sage is a beautiful perennial in the mint family. Sometimes growing to a height of five feet, its burgundy-red tubular flowers are a favorite with the hummingbirds. It is found in Central Texas growing along stream banks amongst the limestone outcroppings. Herbicides, erosion, and the (more)

 

*Sarracenia oreophila 

The majority of the remaining populations of Green Pitcher-plants can be found in the Coosa Valley and Plateau regions of the Cumberland Plateau in northeastern Alabama. The plants grow in acidic soils in moist upland areas and along boggy sandy streams. Following a spring flush of yellow (more)

 

*Sarracenia rubra ssp. jonesii 

Of the 16 historical populations of Mountain Sweet Pitcher-plant, only 10 surviving today. This southern Appalachian endemic continues to face danger from development and the changes it brings to natural communities. Many of the vanished populations were lost as a result of the destruction of (more)

 

*Saussurea weberi 

Weber's saw-wort is a dwarf perennial herb that is 5-20 cm high and arising from a woody rootstock. The lance-shaped leaf blades are coarsely toothed, up to 8 cm long, and have a broad petiole. The alternate leaves are crowded on the stem, reduced, and lacking petioles towards the top. Herbage is (more)

 

*Scaevola coriacea 

Scaevola coriacea is a low, flat-lying perennial herb in the goodenia family (Goodeniaceae). Its older stems are somewhat woody, and the leaves are relatively far apart, giving the plant a sparse appearance. The succulent leaves of this plant are oval- to spoon shaped and are smooth or somewhat (more)

 

*Schiedea adamantis 

This species was first collected on the slopes of Diamond Head Crater on O`ahu, Hawai`i in 1955 and described as a valid new species in 1970. It is a small shrub known only from one population, and has survived in the Diamond Head Crater area despite the growing urbanization of the area. Schiedea (more)

 

*Schiedea apokremnos 

low-branching (more)

 

*Schiedea kaalae 

Schiedea kaalae is a small, sometimes woody perennial with thick, leathery leaves usually tufted at the topmost portion of the stem. Its flowers are borne on large, open panicles. Schiedea kaalae was historically known from the north-central and south-central Waianae Mountains and the northern (more)

 

*Schiedea nuttallii 

Schiedea kaalae is a small, sometimes woody perennial with thick, leathery leaves usually tufted at the topmost portion of the stem. Its flowers are borne on large, open panicles. Schiedea kaalae was historically known from the north-central and south-central Waianae Mountains and the northern (more)

 

*Schiedea spergulina var. leiopoda 

Schiedea kaalae is a small, sometimes woody perennial with thick, leathery leaves usually tufted at the topmost portion of the stem. Its flowers are borne on large, open panicles. Schiedea kaalae was historically known from the north-central and south-central Waianae Mountains and the northern (more)

 

*Schoenocrambe argillacea 

Schoenocrambe argillacea is endemic to a small area in the Uintah Basin, Uintah County, Utah. There are 3 known populations with fewer than 10,000 individuals total. It is a listed threatened species. S. argillacea is an herbaceous perennial and is distinct in having linear to narrowly oblong (more)

 

*Schoenocrambe barnebyi 

This species was listed as Federally Endangered in 1992, and since that time the number of plants in the two remaining populations has increased from approximately 1,000 plants to a little over 2,000 plants (USFWS 1992; Clark and Groebner 2000).

Barneby's reed mustard is a perennial
(more)

 

*Schwalbea americana 

A tall, perennial herb in the figwort family, this plant is distinguished by its large, purplish-yellow, tubular flowers. Schwalbea americana is a hemiparasite that feeds from the roots of a range of associated woody species. Once known historically from the coastal plain extending from (more)

 

*Scirpus ancistrochaetus 

This leafy bulrush in the sedge family is currently known only from about 60 populations scattered from New Hampshire and Massachusetts, south to West Virginia. An obligate wetland plant, Scirpus ancistrochaetus grows in shallow water along the margins of sinkhole ponds (in the south), beaver (more)

 

*Scirpus hallii 

Scirpus hallii, a delicate annual sedge, is a very specialized plant with a narrow habitat tolerance. It is generally found on bare, moist sandy shores of ponds where the water levels fluctuate. It is believed that the changes in water level favor the germination of the plant's seed and also act as (more)

 

*Scirpus longii 

This bulrush is found only in the eastern United States, mainly along the coastal plain, from Nova Scotia to southern New Jersey. A wetland plant, it inhabits open, peaty swales, river meadows, abandoned cranberry bogs, and other areas with fluctuating water levels. The species is notable for its (more)

 

*Sclerocactus brevispinus 

This bulrush is found only in the eastern United States, mainly along the coastal plain, from Nova Scotia to southern New Jersey. A wetland plant, it inhabits open, peaty swales, river meadows, abandoned cranberry bogs, and other areas with fluctuating water levels. The species is notable for its (more)

 

*Sclerocactus cloverae 

Sclerocactus cloverae ssp. brackii is a small, solitary cactus only 3-8 cm tall and 2-7 cm wide. It usually has 4 or 5 central spines, straw colored to brown, and the lower spine is hooked and about 3 cm long. Purple flowers appear from late April to May, and result in small, 1-5 mm long fruits. (more)

 

*Sclerocactus glaucus 

Sclerocactus glaucus, the Uinta Basin hookless cactus flowers from April to May, and after blooming may shrink below the ground. Thus plants are often only visible while blooming, when they have bright pink flowers. S. glaucus and S. parviflorus look similar, but S. parviflorus has a hooked central (more)

 

*Sclerocactus mesae-verdae 

Mesa Verde cactus is found only in Colorado and New Mexico in the Four Corners region. It must withstand temperature extremes from as high as 110 degrees F to as low as 18 degrees F and live with only around 6 inches of rainfall annually. (Spackman et al. 1997) These plants are threatened in the (more)

 

*Sclerocactus wetlandicus 

S. wetlandicus is a barrel-shaped cactus that is endemic to the Uinta Basin of northeastern Utah. Due to its location, it is threatened primarily by oil and gas development. This small cactus averages anywhere from 1.5-7 inches, though larger specimens have been observed. It generally has 6-14 (more)

 

*Sclerocactus wrightiae 

Wright's fishhook cactus was listed as endangered by the U.S. Fish and Wildlife Service in 1979. (USFWS 1979) A small cactus with short spines. The lovely yellowish to pink flowers can be seen in late April to early June. This cactus grows in south-central Utah in salt desert shrub/grass and (more)

 

*Sedum integrifolium ssp. leedyi 

This subspecies is a glacial relic of the Pleistocene that was widespread at the end of the last glaciation but has become extremely rare in the warmer temperatures of post-glaciation climates. Unfortunately, human activities have exacerbated this decline by disturbing the remaining habitat where (more)

 

*Senecio ertterae 

Know your rare plants. A bit of careful observation saved this rare plant from being exterminated by herbicides.

Senecio ertterae requires a very unusual soil containing rhyolitic ash, derived from a particular volcanic rock in the Leslie Gulch area. These specific soil requirements
(more)

 

*Senecio franciscanus 

The San Francisco Peaks groundsel is found only on the talus slopes in the alpine zone on San Francisco Peaks. San Francisco Peaks is a strato-volcano that rises abruptly from 2130 meters (7000 feet) to an elevation of 3852 meters (12,633 feet). This volcano is located north of Flagstaff, (more)

 

*Senecio huachucanus 

This species has a disjunct distribution, occurring on a mountain in Chihuahua, Mexico, and in two mountain ranges in Arizona. (Toolin 1982)

Senecio huachucanus is a perennial herb with a single stem that branches from the middle and grows up to 32 inches (80 cm) tall. Lower leaves are
(more)

 

*Sericocarpus rigidus 

This perennial herb from the Sunflower family (Asteraceae) is distinguished by tightly clustered flower heads on the shoot ends. They are usually in colonies of 50-200+ shoots that spread vegetatively by rhizomes (an underground, horizontal stem). The shoots that are not flowering are usually (more)

 

*Sesbania molokaiensis 

This taxon is now considered synonymous with Sesbania tomentosa. Please refer to the Sesbania tomentosa profile for more (more)

 

*Sesbania tomentosa 

This plant produces amazing large red pea-like flowers that have helped to draw attention to the loss of species on the Hawaiian Islands. Sesbania tomentosa is the only endemic Hawaiian species in the genus and while its numbers have not reached the dire levels of some endemics, it faces several (more)

 

*Shortia galacifolia 

peerennial (more)

 

*Sibara filifolia 

Sibara filifolia, a small annual herb in the mustard family (Brassicaceae), is only found on San Clemente island, part of the Channel Islands of southwestern California. The plant reaches 38cm in height and produces pinkish-purple flowers that bloom from March to April (USFWS 1997). This species (more)

 

*Sidalcea hickmanii ssp. anomala 

Cuesta Pass Sidalcea has multiple, ascending stems from 0.4 to 1 m long. Each stem bears many flowers, which are less than 1 inch in diameter and have bright pinkish lavender petals. This species is a typical "fire follower", with 1000's of plants reported within the first 2-3 years following a (more)

 

*Sidalcea nelsoniana 

Sidalcea nelsoniana exemplifies the ongoing conflict between native ecosystems and the growing population of humans. As of 1997, there were a total of 58 populations/sites known with a total of around 26,500 individuals. While this may seem like an adequate number for a robust species, population (more)

 

*Sidalcea oregana var. calva 

In September of 2001, the U.S. Fish and Wildlife Service caught the attention of many botanists with a promising news release. They had officially designated 6,135 acres of seasonal wetlands as "critical habitat" for the endemic Wenatchee Mountains checker-mallow. The U.S. Fish and Wildlife (more)

 
*Sidalcea stipularis 

 

*Silene alexandri 

erect perennial (more)

 

*Silene douglasii var. oraria 

Three varieties of Silene douglasii are currently recognized (Kephart et al. 1999). Silene douglasii var. douglasii is the most widespread and is found in southern British Columbia, Washington, Idaho, Montana, Utah, Nevada, northern California and eastern and southern Oregon. Silene douglaii var. (more)

 

*Silene perlmanii 

There are three endangered Silene species endemic to Hawai’i (U.S. Fish and Wildlife Service [USFWS] 2001). This particular species, Silene perlmanii, was historically found in two populations on the island of O’ahu, but has not been seen in the wild since 1997, and today exists only in (more)

 

*Silene regia 

This species is one of the Midwest's most beautiful and conspicuous prairie wildflowers, presenting brilliant red flowers during much of the summer. This showy perennial produces 5-petaled crimson-red flowers that are approximately 2 inches in diameter, during the months of June-September. These (more)

 

*Silene seelyi 

Silene seelyi is definitely rare but debatably threatened. The extreme cliff-dwelling habitat of Seely's catchfly protects it from common threats such as anthropomorphic development or competition from invasive species. However with the assistance of ropes, bolts, pulleys and anchors, there is one (more)

 

*Silene spaldingii 

Spalding’s catchfly (Silene spaldingii) is an herbaceous perennial of the intermountain grasslands and sagebrush-steppe of the Pacific Northwest. It is named after Henry Spalding, who first collected it in the mid 1800s near the Clearwater River of Idaho. Like many of its close relatives in the (more)

 

*Silene subciliata 

The Scarlet catchfly is an uncommon wildflower of the East Exas sandylands. It's vibrant orange-red star-shaped flowers are esily noticed on the slopes between upland savannas and forested ravines where it (more)

 

*Sisyrinchium dichotomum 

This species is a narrow endemic found only at four sites in the upper piedmont region of North Carolina. These populations are extremely threatened. Two of them are within highway rights-of-way and another is in an area that was planned for residential development by the private owners. This last (more)

 

*Sisyrinchium sarmentosum 

Contrary to what its common name suggests, the pale blue-eyed grass is not a grass at all. Although its narrow, flat leaves are grass-like, it is a member of the Iris family. Its pale blue (or occasionally white) flowers betray its familial relationship and allow the keen observer to distinguish it (more)

 

*Solanum drymophilum 

Solanum drymophilum is a small, spiny shrub historically found in the eastern and central montane forests of Puerto Rico (Little et al. 1974, Vivaldi and Woodbury 1981). Today, its population is restricted to one site that supports less than 150 individuals (USFWS 1992). In August, 1988 Solanum (more)

 

*Solanum sandwicense 

There are two threatened Solanum species endemic to Hawai’i (U.S. Fish and Wildlife Service [USFWS] 2001). Historically, Solanum sandwicense was known from 12 locations on the islands of O’ahu and Kauai, but now 5 populations exist only on the island of Kauai. All populations of S. sandwicense (more)

 

*Solidago albopilosa 

Solidago albopilosa is a herbaceous perennial tetrapoloid goldenrod, 1-2 ft in height, producing bright yellow, fragrant flowers from September to November and setting seed from October through December. It was discovered by Dr. E. Lucy Braun in 1940 and officially described by her two years later (more)

 

*Solidago houghtonii 

Solidago houghtonii is often accepted as a distinctive species, but its origins continue to be clouded. It is usually a hexaploid and thought to be a naturally occurring hybrid, but the actual parents are the source of controversy. Potential parents could be S. ptarmicoides, S. ohioensis, and S. (more)

 

*Solidago ouachitensis 

Solidago ouachitensis has only been collected four times since it was first collected by G. W. Stevens in 1913. During cooler, moister times this goldenrod species was likely more widespread, but is now restricted to a narrow range within the Ouachita Mountains and is thought to be a relict of the (more)

 

*Solidago plumosa 

Solidago ouachitensis has only been collected four times since it was first collected by G. W. Stevens in 1913. During cooler, moister times this goldenrod species was likely more widespread, but is now restricted to a narrow range within the Ouachita Mountains and is thought to be a relict of the (more)

 

*Solidago shortii 

Short's goldenrod is named after its discoverer, Dr. Charles Short, who found the plant in 1840 growing on a limestone outcrop in Kentucky known as Rock Island. This island was located within the Falls of the Ohio River between Clarksville, Indiana and Louisville, Kentucky. Construction of locks (more)

 

*Solidago spithamaea 

Blue ridge goldenrod is a perennial plant endemic to a very narrow range found on rock outcrops, cliffs, and balds in the Blue Ridge Mountains of North Carolina and eastern Tennessee. Solidago spithamaea grows from short stout rhizomes while erect stem is from 5-10 cm. tall and is usually (more)

 

*Solidago verna 

Solidago verna is the only spring-flowering goldenrod that occurs in the Sandhills and Coastal Plain of the Carolinas. It can be found in a wide array of habitats, including pine savannas, pocosins, and pine barrens. Solidago verna stems can reach 5’ tall and it flowers from late April to June (more)

 

*Solidago villosicarpa 

Solidago villosicarpa is a late-flowering goldenrod with large, bright lemon-yellow floral heads, hairy stems and fruits, mostly hairless leaves, densely villous achenes, and thyrsoid inflorescences. It currently occurs in two counties in the North Carolina Coastal Plain. It was first collected in (more)

 

*Sphaeralcea gierischii 

There is little known about Sphaeralcea gierischii because this species has only recently been described and there are only 9 populations currently known. It is listed as a candidate for protection under the Endangered Species Act. (more)

 

*Sphaeromeria simplex 

The arid basins and plains of Wyoming are a tough place to live. Desert dryness couples with punishing winds and extremes of heat and cold to create an environment not unlike that found high in the mountains. It should not be surprising, then, to find similar plants in both places - dwarf plants (more)

 

*Spigelia gentianoides 

This species is a perennial herb with 1 - 3 stems up to 30 cm tall from a shallow, jointed, ascending rhizome. Stems are usually single, erect, slender but stiff, and maroon tinted. The opposite, sessile leaves are at right angles to the next set of leaves. The lowest leaves (1.5 - 5 cm long) are (more)

 

*Spiraea virginiana 

The West Virginia spiraea is an endemic of the southern Appalachians, which occurs exclusively in the southern Blue Ridge and Appalachian Plateau provinces. Within its area, it is found very sporadically. It was first collected by G. R. Vasey in 1878 in the mountains of North Carolina. (Vasey (more)

 

*Spiranthes delitescens 

Spiranthes delitescens is a slender, erect terrestrial orchid that can grow up to 50 cm in height. Plants have five to ten slender, grass-like leaves which grow basally on the stem. Roots are fleshy and swollen, about 5 mm in diameter. A twisted spike inflorescence may contain up to 40 white (more)

 

*Spiranthes diluvialis 

A beautiful perennial, terrestrial orchid with cream colored flowers. The orchid grow in moist soils on primary or secondary flood plains of rivers or wet, open meadows and springs. This species is known from populations in Colorado, Idaho, Montana, Nebraska, Nevada, Utah, Washington, and (more)

 

*Spiranthes parksii 

The Navasota Ladies'-Tresses is a terrestrial orchid known from four counties in the central part of eastern Texas. The sites are located in oak forested uplands associated with the Brazos River drainages. Cream colored flowers, arranged in a spiral on a thin stemmed spike, bloom in the fall. (more)

 

*Stahlia monosperma 

Stahlia monosperma is a medium-sized evergreen tree endemic to Puerto Rico and Hispaniola (USFWS 1996). This tree can grow up to 50 feet in height and can be found in seasonally flooded wetlands in association with mangrove communities (USFWS 1996). Cobana negra produces an abundance of (more)

 

*Stenogyne kanehoana 

Stenogyne kanehoana was first discovered by Harold St. John in 1934. In 1992, Stenogyne kanehoana was listed under the Endangered Species Act as Endangered: only 2-4 individuals, located on private land, were known to exist. Sometime in the years after listing, all of these plants were (more)

 

*Stephanomeria malheurensis 

The Malheur wirelettuce is face to face with its extinction. After its discovery in 1966, Stephanomeria malheurensis battled drought in the 1970's, a major fire in 1972 followed by invasion of cheatgrass (Bromus tectorum), and heavy rain and flooding from 1981 to 1985. Only one population of (more)

 

*Streptanthus bracteatus 

This beautiful plant is found in Texas Hill country. Once scattered throughout south-central Texas, this species is now thought to be rare, and has been considered for federal status.

The Bracted twistflower is an herbaceous, somewhat succulent waxy annual. It produces beautiful
(more)

 

*Stylisma pickeringii var. pickeringii 

Pickering’s dawnflower is a spreading, herbaceous, perennial vine that forms large mats and clumps primarily in the sandhills and sandy woods of the Southeast. It is usually found in the driest, most barren, deep-sand areas and occasionally colonizing roadsides and other disturbed areas (TNC 1993). (more)

 

*Styrax texanus 

Nestling its roots deep into the limestone cliffs of the Edwards Plateau, the Texas Snowbells (Styrax texana) dangles its delicate white flowers over the crystal clear waters of a Hill Country stream below. This is a beautiful, 10-15 foot tall deciduous shrub with heart-shaped leaves, which are (more)

 

*Swallenia alexandrae 

Swallenia alexandrae is a perennial grass found only in the southern portion of Eureka Valley Sand Dunes system in Inyo County, California (USFWS 1983). The grass forms large clumps across dune slopes and spreads as the shifting sand surrounds newly formed stems. Flowering stalks are 1.5 to 10 dm (more)

 
*Symphyotrichum rhiannon 

 

*Synandra hispidula 

This perennial's leaves are arranged opposite each other, and are simple and serrate. The flowers are large, showy, and yellow and white, and make their appearance during the months of April to June. (Massey 1983)

Very little is known about this
(more)

 
*Talinum humile 

 

*Talinum rugospermum 

This species is of conservation interest as much because it is part of the Karner Blue Butterfly habitat as it is due to its own rarity. This flameflower is thought to be part of the flora of the Great Plains having spread by long distance post-Pleistocene dispersal to become disjunct in the (more)

 

*Tetramolopium capillare 

This species is of conservation interest as much because it is part of the Karner Blue Butterfly habitat as it is due to its own rarity. This flameflower is thought to be part of the flora of the Great Plains having spread by long distance post-Pleistocene dispersal to become disjunct in the (more)

 

*Tetramolopium lepidotum ssp. lepidotum 

There are seventeen Tetramolopium taxa endemic to Hawai’i, seven of which are threatened (U.S. Fish and Wildlife Service [USFWS] 2001). Tetramolopium lepidotum has two recognized subspecies: ssp. lepidotum, discussed here, and ssp. arbusculum, which is known only from one specimen collected in (more)

 

*Tetramolopium remyi 

decumbent or occasionally erect (more)

 

*Tetraneuris herbacea 

Tetraneuris herbacea is a stunning plant, both in its flower and its ability to survive. From late April to mid-May a carpet of sunny yellow flowers can be seen covering limestone pavement of the Lakeside Daisy State Nature Preserve, near the town of Lakeside, Ohio. The flowers all turn to follow (more)

 

*Tetraplasandra oahuensis 

The most variable species of this endemic genus, Tetraplasandra oahuensis has large pinnate compound leaves with 7 to 15 leaflets, the lowest opposite pair usually smaller than the rest. Leaf surfaces are dull. The petiole is about the same length as the rachis. Sap is clear. The black to purple (more)

 

*Thalictrum cooleyi 

Cooley's meadowrue is endemic to the coastal plain in the southeastern United States. This plant occurs in fire-dependent web bogs and savannas. The main causes for the decline of the species can be attributed to fire suppression and loss of habitat due to agricultural/silvicultural practices. (more)

 

*Thalictrum heliophilum 

In contrast to the habitat of the more common meadowrues, the sun-loving meadowrue prefers the intensely hot and dry shale slopes of Colorado's Piceance Basin. Thalictrum heliophilum is dioecious, and therefore male and female flowers are found are separate plants. Future oil shale development in (more)

 

*Thalictrum texanum 

Dioecious perennial from a cluster of small, orange-yellow, carrot-like roots that become black when dry. Stems erect or sprawling, 4-18" tall. Bears clusters of small white flowers February- (more)

 

*Thelesperma pubescens 

Thelesperma pubescens is limited to the Bishop Formation and perhaps adjacent areas in Uinta land Sweetwater Counties, Wyoming. This species has been separated from T. caespitosum by pubescence of the leaves (Dorn 1972). “With the discovery of mixed populations of plants with pubescent and (more)

 

*Thelypodium eucosmum 

When in full bloom, the beautiful pink-purple flowered inflorescences and arrow-shaped leaves of Thelypodium eucosmum create spectacular show. These tall and spindly members of the mustard family stand out against the otherwise brown and gray sagebrush-covered hillsides of eastern Oregon. This (more)

 

*Thelypodium howellii ssp. spectabilis 

Thelypodium howellii ssp. spectabilis is found only in five populations, all in the Baker-Powder River Valley region bordered by the Wallowa and Elkhorn Mountains in northeastern Oregon. This member of the mustard family is listed as Endangered by the State of Oregon and Threatened by the Federal (more)

 
*Thelypteris patens 

 

*Thelypteris sclerophylla 

Thelypodium howellii ssp. spectabilis is found only in five populations, all in the Baker-Powder River Valley region bordered by the Wallowa and Elkhorn Mountains in northeastern Oregon. This member of the mustard family is listed as Endangered by the State of Oregon and Threatened by the Federal (more)

 

*Thermopsis macrophylla 

Fewer than 2500 plants survive within a relatively narrow band about 3 miles long along the crest of the central Santa Ynez Mountains in Santa Barbara County, California. Current populations consist of plants similar in age and may be several decades old, because seeds germinate only after (more)

 

*Thymophylla tephroleuca 

Ashy dogweed is an attractive perennial wildflower. The ashy grayish-green stems and leaves of this plant give it its name. After rains, the beautiful ashy dogweed blooms bright yellow daisy-like flowers against a mound of gray-green foliage from March to May. It grows in a sandy, (more)

 

*Thysanocarpus conchuliferus 

Ashy dogweed is an attractive perennial wildflower. The ashy grayish-green stems and leaves of this plant give it its name. After rains, the beautiful ashy dogweed blooms bright yellow daisy-like flowers against a mound of gray-green foliage from March to May. It grows in a sandy, (more)

 

*Tillandsia baileyi 

Ashy dogweed is an attractive perennial wildflower. The ashy grayish-green stems and leaves of this plant give it its name. After rains, the beautiful ashy dogweed blooms bright yellow daisy-like flowers against a mound of gray-green foliage from March to May. It grows in a sandy, (more)

 

*Torreya taxifolia 

Torreya taxifolia is a small, conical tree of the yew family (Taxaceae) and a close relative to Taxus brevifolia from which the cancer drug Taxol is derived. T. taxifolia, or stinking cedar, is an extremely rare conifer that once towered fifty feet above the forested ravines of the Apalachicola (more)

 

*Townsendia aprica 

Listed as a threatened species in 1985 (USFWS 1985). A stemless, low-growing perennial with leaves and flowers that are born at ground level. Flowers are disproportionately large with yellow to golden rays. The lastchance townsendia is a specialist on Arapien and Mancos Shale formations and (more)

 
*Trichomanes punctatum ssp. floridanum 

 

*Trichostema austromontanum ssp. compactum 

Trichostema austromontanum subsp. compatcum (Hidden lake bluecurls) is a member of the mint family (Lamiaceae). This taxon is very small and is only about 10 cm tall. Hidden Lake blue curls is known to occur at one location in the world, in the San Jacinto Mountains in Riverside, County. (more)

 

 

*Trifolium leibergii 

In Oregon, Trifolium leibergii is restricted to an area that ranges 2 miles on either side of the Middle Fork of the Malheur River and continues for approximately 10 miles. Here, it grows on a distinct habitat characterized by a thin, gravelly soil layer consisting of decomposing (broken-down) (more)

 

*Trifolium stoloniferum 

From 1940 until 1985, running buffalo clover was thought to be extinct. Then two populations were rediscovered in West Virginia. Since that initial rediscovery, a number of populations have been found in five of the eight states of this species' original distribution.

A story of the
(more)

 

*Trifolium thompsonii 

Trifolium thompsonii probably doesn't look like any other clover you've ever seen. It grows up to two feet tall and its large, spherical, reddish-lavender flower heads rise above the swaying grass like a sea of cheerleader pom-poms. Unlike most clovers, the leaves of this plant are comprised of 3 (more)

 

*Trillium texanum 

Rhizomatous perennial forming colonies of 4-12 inch tall flowering stems with leaf-like, grayish-green bracts in a single whorl at stem apex. Non-blooming stems have 1-3 deep green leaves. Flowers are showy, three-petalled, white but becoming pink & finally reddish with (more)

 

*Tripsacum floridanum 

Tripsacum floridanum is a smaller relative of the more common T. dactyloides (Eastern Gamagrass), distinguished primarily by slightly wider leaf blades, usually less than one meter (three feet) tall and usually having solitary spikes (Hitchcock 1951). In southern Florida, T. floridanum is listed (more)

 

*Trollius laxus ssp. laxus 

To date, this species is found in approximately 40 populations, most of them with fewer than 100 individuals, in eastern North America. Conservation activities for this species are numerous in its range, and include monitoring, seed banking (three occurrences), ecology and population genetics (more)

 

*Tropidocarpum capparideum 

To date, this species is found in approximately 40 populations, most of them with fewer than 100 individuals, in eastern North America. Conservation activities for this species are numerous in its range, and include monitoring, seed banking (three occurrences), ecology and population genetics (more)

 

*Tumamoca macdougalii 

This desert-growing perennial vine is a member of the gourd family, with a tuberous root and foliage that is made up of climbing tendrils. When the foliage of this plant is touched, a fetid smell is given off. Flowers are a greenish-yellow and separated by gender. Male flowers outnumber female (more)

 

*Vaccinium sempervirens 

Rayner’s Blueberry is a small trailing or spreading heath found in Atlantic white cedar bogs and seepage slopes and endemic to Lexington County in the Sandhills of South Carolina. It produces few small white flowers in late March to early April and even fewer fruits. The leaves of Rayner’s (more)

 

*Valerianella texana 

Rayner’s Blueberry is a small trailing or spreading heath found in Atlantic white cedar bogs and seepage slopes and endemic to Lexington County in the Sandhills of South Carolina. It produces few small white flowers in late March to early April and even fewer fruits. The leaves of Rayner’s (more)

 

*Viburnum bracteatum 

The name "arrowwood" belongs to a larger species, V. dentatum, that probably includes V. bracteatum. Indians used strong shoots of these viburnums for the shafts of their arrows. Bracted viburnum is a deciduous shrub up to 3 m tall that is different from other arrowwoods in its special habitat, (more)

 

*Viburnum dentatum var. venosum 

The southern arrowwood is a native shrub that grows from 3 to 9 feet tall. Its leaves are deciduous, opposite, simple, and oval-shaped with coarsely but regularly toothed margins. These shiny green leaves turn yellow to reddish-purple in the late fall. Flowers bloom in May and early June, and are (more)

 

*Vicia menziesii 

Vicia menziesii is a vine that grows on the eastern slopes of Mauna Loa and Mauna Kea on the Island of Hawai`i. Its extensive branching system typically climbs into the subcanopy of the forest and can reach lengths of up to 60 feet. Each vine is known to produce more than 200 pinkish-rose flowers (more)

 

*Viola chamissoniana ssp. chamissoniana 

There are four threatened Viola species endemic to Hawai’i (U.S. Fish and Wildlife Service [USFWS] 2001). Viola chamissoniana itself has three recognized subspecies found on numerous Hawaiian islands (ssp. chamissoniana, ssp. robusta, and ssp. tracheliifolia). (Wagner et al. 1999) Of these (more)

 

*Viola helenae 

small, erect, unbranched (more)

 

*Viola lanaiensis 

Viola lanaiensis is one of seven species of violets native to the Hawaiian Islands, and is one of three species of Hawaiian violets listed as endangered by both Federal and State governments. Viola lanaiensis is restricted to the island of Lana`i, where fewer than 80 plants still survive in (more)

 

*Warea amplexifolia 

Warea amplexifolia is also known as 'clasping warea' or 'wide-leaf warea'. Clasping warea is an erect annual herb in the mustard family. These plants grow from 30 to 100 cm tall. The stalk may be unbranched, or often branching midway up the stem. The leaves of a young plant are slightly folded (more)

 

*Warea carteri 

This rare plant was historically much more widespread than it is today. All known populations in Brevard, Broward, Miami-Dade, DeSoto and Glade counties have been extirpated, and the species is now found only on the Lake Wales Ridge in Lake, Polk, and Highlands counties, Florida. The main cause (more)

 

*Wilkesia hobdyi 

The genus Wilkesia (Asteraceae) contains two species endemic to Kaua’i. One of these, Wilkesia hobdyi, is threatened. This plant is currently found only on nearly vertical rock outcrops in western Kaua’i, and is threatened by the actions of feral goats.

Goats were brought to the
(more)

 

*Xerophyllum asphodeloides 

Xerophyllum asphodeloides is a very unusual plant, and one of only two species in its genus in North America. Its various common names (beardtongue, turkeybeard) refer to the tuft of grass-like, long leaves that rings the base of the single, tall inflorescence bursting with showy white flowers. (more)

 

*Xylosma crenata 

Xylosma crenatum is a unisexual (produces either male or female flowers) tree which grows up to 46 feet tall. It was first collected in 1917 by Charles Forbes but remained undiscovered for decades due to a misidentification. Over 50 years later, a second collection was made in 1968 by Robert (more)

 

*Yermo xanthocephalus 

The Wind River Basin of central Wyoming is home to a remarkable number of rare plants, but none as rare as the desert yellowhead, a wildflower that was only discovered in 1990, and whose entire global distribution is limited to about 6 acres of cold desert habitat here. The genus name, Yermo, is a (more)

 

*Yucca necopina 

Essentially stemless shrub forming small colonies with a basal cluster of stiff succulent leaves and a woody stalked inflorescence held above the leaves, 3-9 feet tall. Leaf margins white with curling fibers. Flowers pendant in an unbranched spike or a short branched panicle to 3 1/2 feet long. (more)

 

*Zanthoxylum coriaceum 

Shrub or small tree to 7 m tall. Stems armed with prickles. Leaves imparipinnate, infrequently paripinnate, (3-) 5-7-foliolate, (6-) 9-14(-18) cm long; central leaf stalk not winged; leaflets leathery, oblong to elliptic, ovate or obovate, with apex acute to acuminate or emarginated, larger (more)

 

*Zanthoxylum dipetalum var. tomentosum 

Zanthoxylum dipetalum is a tree that can grow up to 15 meters tall with a trunk that can grow as large as 30 cm in diameter. The yellowish wood of this species was used by early Hawaiians for tools as well as instruments used for long distance communication. There are two recognized varieties of (more)

 

*Zanthoxylum parvum 

The bark, leaves, and fruit of species in the genus Zanthoxylum have historically been used medicinally, especially in Latin America. It is said to treat various ailments, including toothaches, intestinal problems, and rheumatism. (Powell 1988) In addition to these medicinal uses, species in the (more)

 

*Zanthoxylum thomasianum 

Zanthoxylum thomasianum, an evergreen shrubby-tree, can grow up to 20 feet in height in the semi-evergreen forests of Puerto Rico and the U.S. Virgin Islands. Its trunk reaches up to 4 inches in diameter and is covered by thick spines. The bark, leaves, and fruit are all aromatic. Small male and (more)

 

*Zizania texana 

Texas wild rice is an aquatic herbaceous perennial which can be found growing only in the cool, clear waters of the San Marcos River in Texas. This species was so abundant in the 1930's that the local irrigation company considered it difficult to keep this plant from clogging its ditches. In (more)

 

*Ziziphus celata 

Florida ziziphus (Ziziphus celata) is one of the rarest and most imperiled plants in Florida. It is so rare that the taxonomists who named it thought they were describing an extinct species. And given its limited geographic distribution, small populations, lack of genetic diversity and reluctance (more)


 

 
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