CPC National Collection Plant Profile

Lomatium cookii

Tom Kaye

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CPC National Collection Plant Profile

Lomatium cookii

Common Names: 
Agate Desert lomatium, Cook lomatium, Cook's lomatium
Growth Habit: 
CPC Number: 


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 Fish & WildLife

Lomatium cookiienlarge
Photographer: Tom Kaye

Lomatium cookii 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.

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 (Limnanthes floccosa ssp. grandiflora) in the vernal pools of the Agate Desert (Kagan 1986). Both species were proposed as endangered by the Fish and Wildlife Service in May of 2000 (USFWS 2000a, 2000b).

Vernal pool habitat was once widespread south of the Rogue River in Oregon. It has now been virtually eliminated. Land has been converted to pasture, agricultural fields, commercial and industrial complexes, and housing developments. Areas not impacted directly by development have had their hydrology altered by nearby construction: construction of parking lots and roads has led to increased water run-off and higher water levels in the vernal pools in some areas, while irrigation ditches and activities that altered the hardpan clay layer in the soil led to decreased water levels in other areas. Both situations were detrimental to Lomatium cookii, which depends on seasonal inundation. Development of land also created fragmented populations, leading to decreased gene flow. This may eventually prove to be detrimental to the populations.

Distribution & Occurrence

State Range
State Range of  Lomatium cookii
  Populations in the Agate Desert are found on the margins and bottoms of vernal pools with standing water from December to April or May. Populations in the Illinois Valley can be found in moist, grassy meadows.

  OR: Klamath Mountains: "Agate Desert" in Jackson County and the Illinois Valley in Josephine County

Number Left
  As of 2000: 13 occurrences in the Agate Desert, Jackson County and 10 in French Flat, Josephine County. Total occupied habitat is about 200 acres. Mapped potential habitat totals 133 acres in the Agate Desert, but recent disturbances have limited occupied habitat to approximately 69 acres. In French Flat, about 150 acres of habitat is occupied (USFWS 2000a). The largest French Flat population consists of an estimated 207,000 individuals, while many populations contain fewer than 50 (Kaye 2000a, 2000b).


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 10/27/1989  

Conservation, Ecology & Research

Ecological Relationships
  • To prevent self-pollination, stigmas (female parts) are exposed and receptive to pollen prior to anther dehiscence (pollen release) on the same flower (Kagan 1986).
• Flowering stems emerge from a rosette in late February and flowers appear from mid-March through May. The earliest umbels (clusters of small flowers) are predominantly staminate (male) while later have both staminate and hermaphroditic (male and female) flowers (some other Lomatium species share this characteristic). Plants that only produce one umbel produce few, if any fruits (Kaye 2000a, 200b).
• Observed pollinators include a small bee in the Andrerae family (Brock 1987 in Kaye 2000b), a small black moth (Kagan 1986 in Kaye 2000b) and several bumblebees (Bombus spp.) (Kaye 2000b).
• The Agate Desert populations and French Flat populations have slight morphological differences, but the differences are not considered great enough to separate them into subspecies (USFWS 2000a).
• Plants such as Lomatium cookii that live in vernal pools are adapted to grow, flower, and set seed during the short time that water is available in the spring (USFWS 2000a).
• Seeds of Lomatium cookii are not able to germinate under the heavy thatch created by many non-native grasses that have begun invading (USFWS 2000a).

  • Habitat loss due to industrial, commercial, agricultural, and residential development (USFWS 2000a).
• Changes in hydrology of vernal pools due to:
• ORV use. When driven in moist areas, ORV tires create large ruts and can fracture the clay hard pan layer. This allows water to drain, affecting plant survival. It is estimated that ORV use has caused the drainage of 15 acres at French Flat (USFWS 2000a).
• Irrigation ditches drain water from vernal pools (Kaye 2000a, 2000b).
• Dredging for gold in surrounding hills increases run-off (USFWS 2000a).
• Road construction increases run-off (Kaye 2000).
• Logging in surrounding mountains increases run-off (USFWS 2000b).
• Livestock grazing (USFWS 2000b). Much available habitat has been grazed. In areas with heavy grazing, no Lomatium cookii plants are present (Kagan 1986).
• Woody plant encroachment due to fire suppression (USFWS 2000b).
• Invasion of non-native annual grasses. Native seeds such as Lomatium cookii are not able to germinate under the dense thatch created by annual grasses (USFWS 2000a).
• Herbicide spraying, mowing, grading, and other road maintenance activities (USFWS 2000a).

Current Research Summary
  • Seed germination trials were done at the Berry Botanic Garden. Three batches of seeds (11, 12, and 16 years old) were subjected to 4 sets of environmental conditions with two variables: length of cold stratification and growth chamber temperature regime. Cold stratification for 8 or 16 weeks followed by 68°F (20°C) or 50°/68°F (10°/20°C) treatment resulted in 20-100% germination depending on the parent plant. No one treatment was consistently better than the others. The 16 year old accession, stored since the first year the seed bank was in operation (1983), yielded a maximum of 90% germination (8 weeks of cold stratification followed by alternating 10°/20°C (50°/68°F) (Gasser 1999).
• Demographic monitoring from 1994 through 1999 at populations on Bureau of Land Management (BLM) land. Transition matrices were prepared to assist in determining population trends (Kaye 2000a, 2000b).
• Preliminary genetic work (using AFLPs?) has not revealed any differences between the Agate Desert and French Flat populations (Gitzendanner, M. at Washington State University (now at the University of Florida)).
• A study of effective management tools. Plots containing Lomatium. cookii were subjected to one of three treatments: raked, raked and scarified, or left as a control. Germination and seedling survivorship were greatest in the raked plots (D. Borgias in U.S. Fish and Wildlife Service (USFWS) 2000a).

Current Management Summary
  • Three populations occur on Oregon Department of Transportation (ODOT) Land. According to the ODOT website, they are under "special management"
• The largest known population is in the Agate Desert and is managed by The Nature Conservancy. Here, they manage approximately 17 acres of Lomatium cookii habitat.
• The Nature Conservancy attempted to salvage 140 plants from an area that was to be graded for road construction on private property. Although the landowner approved removal of the plants, only one individual was salvaged before grading occurred. It died after transplantation (USFWS 2000a).
• Seeds from 3 locations in Jackson County (Agate Desert) and 2 locations in Josephine County (French Flat) are stored at The Berry Botanic Garden.
• One site in French Flat is designated as an Area of Critical Environmental Concern (ACEC).

Research Management Needs
  • Fence land to restrict access.
• Restrict Off-Road Vehicle (ORV) use on BLM land and Agate Desert Preserve.
• Mowing, burning, light grazing or raking of habitat after seed maturation but before fall growth to reduce plant cover from exotic grasses (Brock in USFWS 2000a).
• Continued monitoring on managed lands (BLM land and Agate Desert Preserve).

Ex Situ Needs
  • Collect and store adequate numbers of genetically representative seeds.
• Determine germination requirements. Initial germination trials were inconclusive. Attempt with larger sample sizes.
• Determine propagation and re-introduction protocols.


Books (Single Authors)

Eastman, D.C. 1990. Rare and Endangered Plants of Oregon. Beautiful America Publishing Company. 194p.

ONHP. 2001. Rare, Threatened and Endangered Plants and Animals of Oregon.

Electronic Sources

DiTomaso, J. (2001). UC Weed Research and Center Yellow Starthistle Information. University of California, Davis. http://wric.ucdavis.edu/yst/impacts/impacts.pdf. Accessed: 2002.

Journal Articles

Gitzendanner, M.A.; Soltis, P.S. 2001. Genetic variation in rare and widespread Lomatium species (Apiaceae): A comparison of AFLP and SSCP data. Edinburgh Journal of Botany. 58, 2: 347-356.

Hartman, R.L.; Nelson, B.E. 1998. Novelties from North America north of Mexico: A 20-Year Vascular Plant Diversity Baseline. 51 pp.

Kagan, J.S. 1986. A new species of Lomatium (Apiaceae) from southwestern Oregon. Madroρo. 33: 71-75.

USFWS. 2000. Endangered Species Bulletin. 25, 4

USFWS. 2000. Proposed Endangered Status for the Plants Lomatium cookii (Cook’s lomatium) and Limnanthes floccosa ssp. grandiflora (Large-Flowered Wooly Meadowfoam) in Oregon. Federal Register. 65, 94: 30941-30951.

Newspaper Articles

2001 June 14, 2001. Holding on for Life: Local endangered species survive in isolated patches. Eugene Weekly-Online Edition; Volume XX No. 24.


Boragias, D.D. 1993. Fire effects on the Rogue Valley mounded prairie on the Agate Desert, Jackson County, Oregon. Portland, Oregon: The Nature Conservancy. Unpublished.

Gasser, D.A.S. 1999. The germination regimes for rare and endangered members of the Umbelliferae and Compositae Families. Unpublished report on work conducted at the Berry Botanic Garden for academic credit, by a Lewis and Clark College Student. On file at the Berry Botanic Garden.

Kaye, T.N. 2000. Effect of population monitoring on Cook's desert parsley (Lomatium cookii). Unpublished report funded jointly by the U.S. Fish and Wildlife Service and the Oregon Department of Agriculture, Plant Conservation Biology Program.

Kaye, T.N. 2000. Lomatium cookii: Population Monitoring in the Illinois Valley, Josephine County, Oregon. Unpublished progress report prepared for the UDSI Bureau of Land Management, Medford District, and the Institute for Applied Ecology.

Knight, L.; Seevers, J. 1992. Special Status Plants of the Medford District BLM. Medford, Oregon: Bureau of Land Management-Medford District. p.228.

  This profile was updated on 7/8/2010
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