CPC National Collection Plant Profile

Plagiobothrys hirtus var. hirtus


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CPC National Collection Plant Profile

Plagiobothrys hirtus var. hirtus

Common Names: 
popcorn flower, rough popcorn flower
(Greene) Johnst.
Growth Habit: 
CPC Number: 


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 Fish & WildLife

Plagiobothrys hirtus var. hirtusenlarge
Image Owner: Oregon Natural Heritage Data Base

Plagiobothrys hirtus var. hirtusenlarge
Photographer: Ed Guerrant

Plagiobothrys hirtus var. hirtus is Fully Sponsored
Primary custodian for this plant in the CPC National Collection of Endangered Plants is: 
Edward Guerrant, Ph.D. contributed to this Plant Profile.

Plagiobothrys hirtus var. hirtus

The native wetlands occupied by this species offer a unique combination of intertwining aquatic and terrestrial life. Many native annual plants, including skullcap speedwell (Veronica scutellata), Willamette downingia (Downingia yina), and Douglas' meadow-foam (Limnanthes douglasii), as well as a wide variety of aquatic invertebrates depend on the seasonal wetlands for their success and survival. Rough popcornflower is an obligate wetland plant and requires vernal pools to complete its lifecycle. It must remain submerged in standing water from late fall to early spring. The destruction of wetlands in Douglas County, Oregon that results from housing and road construction as well as grazing will lead to extinction of rough popcorn flower if preventative measures are not taken. Both habitat protection and reintroductions of this species are potential mechanisms for the conservation of this species. This species is a good candidate for reintroduction as it germinates readily and can be cultivated in a greenhouse setting.

Distribution & Occurrence

State Range
State Range of  Plagiobothrys hirtus var. hirtus
  Plagiobothrys hirtus ssp. hirtus is found only in seasonal wetlands that are inundated by water from late fall to early spring (vernal pools) at lower elevations (approximately 300 to 500 ft or 100 to 150 m).

  OR: Klamath Mountains region, Umpqua River Drainage, in an area approximately 25-30 miles long in Douglas County, Oregon.

Number Left
  17 known occurrences. 15 are naturally occurring, 2 are reintroduced. Of the naturally occurring populations, only 5 are legally protected. Two are on Oregon Department of Transportation land and 3 are on private land managed by The Nature Conservancy. The remaining populations are on private commercial, residential and agricultural land. There is an estimated 7,000 individuals, with patch sizes ranging from 1 to 3,000 individuals. However, since Plagiobothrys hirtus ssp. hirtus can spread vegetatively, it is difficult to estimate the total number of genetic individuals. Total occupied habitat is only about 45 acres (USFWS 2000).


Global Rank:  
Guide to Global Ranks
Federal Status:  
Guide to Federal Status
Recovery Plan:  

State/Area Protection
  State/Area Rank Status Date  
  Oregon S1 LE 10/27/2001  

Conservation, Ecology & Research

Ecological Relationships
  • Plagiobothrys hirtus ssp. hirtus is an obligate wetland plant. Like many vernal pool or seasonal wetland species, this plant has two distinct growth forms. Seeds germinate in the fall when the rains begin to fill the pools and swales. The seedlings overwinter as submerged rosettes. The leaves are terete, not hairy, and they have many air spaces which aid in carbon dioxide assimilation. When the water recedes in late spring, flowering stems develop. The new leaves produced are long and linear with hairy margins (USFWS 2001).
• Plagiobothrys hirtus ssp. hirtus is intolerant of shading. Under shade, plants have reduced vigor, lower reproduction, lower seedling recruitment and lower seedling establishment than plants that are not shaded. Historically, occasional burning by Native Americans or lightening caused fires most likely kept native oaks and ash from growing at pool edges
• Unlike other species of this genus, P. hirtus is thought to be a short to long-lived perennial. It may behave as an annual depending on the environmental conditions. If pools do not dry completely in the summer, plants remain green throughout the fall, are submerged by fall rains, and adopt the aquatic morphology. If pools dry completely during the summer, plants die after flowering and setting seed (USFWS 2001).
• Significant genetic variation may exist between populations. Timing of blooming, number of flowers per plant, number of flowers per inflorescence as well as the tendency to persist as a perennial all appear to be genetically controlled and variable between populations (USFWS 2001).
• Plagiobothrys hirtus ssp. hirtus spreads by rhizomes to form mats of genetically identical plants, which increase its ability to persist and dominate an area (Amsberry 2001).

  • Destruction of wetlands due to drainage for agricultural uses. Pools adjacent to altered land may also be effected due to the changes in hydrology (USFWS 2001).
• Wetland destruction due to urban development (USFWS 2001).
• Heavy spring and summer grazing by cattle and sheep. Limited grazing may help to control exotic weeds and remove thatch buildup (USFWS 2001).
• Invasive exotic weeds such as teasel (Dipsacus sylvestris), knapweed (Centaurea sp.), Himalyan blackberry (Rubus discolor), and pennyroyal (Mentha pulegium) (USFWS 2001).
• Fire suppression resulting in encroaching native oaks and ash trees which shade Plagiobothrys hirtus ssp. hirtus (USFWS 2001).
• Reduced gene flow due to habitat fragmentation (USFWS 2001).

Current Research Summary
  • Little research done prior to 1995 (USFWS 2001).
• Observations and preliminary genetic research suggest that there are three genetically distinct groupings of populations (USFWS 2001).
• Researchers at the Oregon Department of Agriculture (ODA) and Oregon State University (OSU) have completed projects on genetic variation, reproductive biology, and life history traits (USFWS 2001).
• A graduate student at Oregon State University evaluated the life history and ecology of Plagiobothrys hirtus ssp. hirtus through greenhouse and field studies. She used greenhouse transplants to augment two native populations. She discovered that P. hirtus is a facultative perennial, not strictly an annual as previously thought (Amsberry, pers. comm. 2001).
• Germination trials were conducted at the Berry Botanic Garden. Seeds were first subjected to either 8 weeks of cold stratification or no cold stratification. Seeds were then placed in either constant 68°F (20°C) or alternating 50°/68°F (10°/20°C). 67% of seeds that were cold stratified and then placed in constant temperatures geminated while only 27% of seeds that were cold stratified and then placed in alternating temperatures germinated. When seeds were not cold stratified, 0% of seeds germinated under constant temperatures while 67% germinated under alternating temperatures (BBG File).

Current Management Summary
  • Listed as Endangered by the U.S. Fish and Wildlife Service and the state of Oregon, however, neither listing protect plants found on private land.
• Plagiobothrys hirtus ssp. hirtus is marginally protected by the Clean Water Act as it occurs in wetlands. The law requires permits for any action that would fill, dredge, or otherwise damage wetlands. However, farm use exemptions and the fact that permits are usually issued readily, means that many wetlands get destroyed despite the law (USFWS 2001).
• Experimental reintroduction at two sites on the North Bank Habitat Management Area (a BLM Area of Critical Environmental Concern).
• Five patches are currently protected. Two are on Oregon Department of Transportation right-of-ways, three are on land managed by The Nature Conservancy.
• Inventories for new populations were conducted in the 1980's by James Kagan (ONHDB 2000) and ODA in 1998.
• A recovery plan was drafted in 2001. The goal of the plant is to meet specific conditions in order to downlist the plant by 2011 (USFWS 2001).

Research Management Needs
  • Determine the effect of fire on Plagiobothrys hirtus ssp. hirtus.
• Study the interaction of P. hirtus ssp. hirtus and other organisms, such as herbivores, in the ecosystem.
• Study the effect of different grazing regimes (time, intensity, grazer, etc) on the success of P. hirtus ssp. hirtus (USFWS 2001).

Ex Situ Needs
  • Collect and store a genetically representative sample of seeds from across the range.


Books (Single Authors)

Gray, A.; Fernald, M.L. 1987. Gray's manual of botany: a handbook of the flowering plants and ferns of the central and northeastern United States and adjacent Canada. Portland, Or.: Dioscorides Press. 1632p.

Meinke, R.J. 1982. Threatened and Endangered Vascular Plants of Oregon: An Illustrated Guide. Portland, Oregon: U.S. Fish & Wildlife Service, Region 1. 326p.

Radford, A.E.; Ahles, H.E.; Bell, C.R. 1968. Manual of the vascular flora of the Carolinas. Chapel Hill, NC: University of North Carolina Press. 1183p.

Voss, E.G. 1996. Michigan Flora Parts I, II, and III. Cranbrook Institute of Science and University of Michigan Herbarium.

Electronic Sources

ONHDB. (2000). Oregon Natural Heritage Program Database. Portland, Oregon.

Journal Articles

1935. Studies in the Boraginaceae, XI (Original Publication). Journal of the Arnold Arboretum. 16: 193.

Amsberry, K.; Meinke, R. 1997. Restoring the popcorn- flower (Plagiobothrys hirtus), in Oregon. Endangered Species Technical Bulletin. 22, 2: 12-13.

Dellavalle, M.J.; Simpson, M.G. 1997. New taxonomic characters in the genus Plagiobothrys in the family Boraginaceae. Microscope Research Techniques. 36, 4: 346-346.

Hultén, E. 1968. A Manual of the Vascular Plants. Flora of Alaska and Neighboring Territories. 1008 pp.

USFWS. 1976. Proposed Endangered Status for 1700 U.S. Plants. Federal Register. 41: 24523-24572.

USFWS. 1996. Notice of Reclassification of 96 Candidate Taxa. Federal Register. 61, 40: 7457-7463.

USFWS. 2000. Endangered Status for the Plant Plagiobothrys hirtus (Rough Popcornflower). Federal Register. 65, 16: 3866-3875.

USFWS. 2000. Regional News, Recovery Updates, & Listing Actions. Endangered Species Technical Bulletin. 25, 1-2: 1-7.

Personal Communications

Amsberry, K. 2001. Personal Communication. Kelly Amsberry, Oregon Department of Agriculture, Corvallis, Oregon.


Gamon, J.; Kagan, J. 1985. Status report for Plagiobothrys hirtus. Portland, Oregon: Oregon Natural Heritage Program.

USFWS. 2001. Draft rough popcorn flower (Plagiobothrys hirtus) Recovery Plan. Portland, Oregon: U.S. Fish and Wildlife Service. p.54.


Amsberry, K. 2001. Conservation biology of Plagiobothrys hirtus (Boraginaceae): evaluation of life history and population enhancement. [M.S. Thesis]: Oregon State University. Corvallis, Oregon. 132p.

  This profile was updated on 3/4/2010
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