*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 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, with leaves rarely longer that 10 cm (Shreve and Wiggins 1994). The cordate leaves are extremely velvety and the reverse side is much (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)

*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 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 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)

*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 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)

*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 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)

*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)

*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 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 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 (more)

*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)

*Aster curtus 
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)

*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 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 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 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 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 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 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 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)

*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)

*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)

*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)

*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)

*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)

*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 meters 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)

*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 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 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)

*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)

*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)

*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 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 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)

*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)

*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)

*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)

*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 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 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)

*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 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 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 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 humilis var. 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 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 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)

*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 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)

*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)

*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)

*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 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)

*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 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)

*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 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 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 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 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)

*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)

*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)

*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)

*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)

*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)

*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 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 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 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 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 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)

*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)

*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)

*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)

*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)

*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)

*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 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 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 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)

*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)

*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)

*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)

*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)

*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)

*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 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)

*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)

*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 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)

*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 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)

*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)

*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)

*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)

*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 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)

*Oxybaphus rotundifolius 
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)

*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 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)

*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 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 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 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)