Cook's lomatium potentially occurs in these Oregon counties: Jackson, Josephine (Map may reflect historical as well as recent sightings)
Cook's lomatium was listed as endangered in 2002 (U.S. Fish and
Wildlife Service 2002). Critical habitat was designated in July 2010.
Description and Life History
Cook's lomatium is a small perennial plant (1.5-5 dm or 0.5-1.6
ft tall) in the parsley family (Apiaceae), with a slender, twisted
taproot. The taproot often branches at ground level, forming multiple
stems. An umbel of pale yellow flowers develops boat-shaped fruits
8-13 mm (0.3-0.5 in) long with thickened margins. The leaves are
smooth, finely dissected, and strictly basal. Flowering typically
occurs from mid-March through mid-May.
This plant occurs only where soil types have a hard pan or clay
pan layer close to the soil surface, creating seasonally wet soils
and vernal pools. The Agate Desert is characterized by shallow,
Agate-Winlow soils, a relative lack of trees, sparse prairie vegetation,
and agate on the soil surface. Associated species in the Agate
Desert include meadowfoams (Limananthes floccosa ssp. grandiflora
- also proposed for listing- and L. f. ssp. floccosa), Plagiobothrys
bracteatus (no common name), and Navarretia spp. Associated species
at French Flat include California oatgrass (Danthonia californica),
Plagiobothrys bracteatus, shaggy horkelia (Horkelia congesta),
short-stemmed star tulip (Calochortus uniflorus), and sedge-leaf
buckbrush (Ceanothus cueatus).
Reasons for Decline
Industrial, commercial, and residential development, road and
power-line construction and maintenance, livestock grazing, agricultural
conversion, weed competition, mowing, and roadside spraying have
all contributed to the decline of this species. In Josephine County,
Cook's lomatium is also threatened by gold mining, logging, fire
suppression, and uncontrolled off-road-vehicle use.
This species is known from the Agate Desert near Medford, Jackson
County, Oregon and French Flat in the Illinois Valley in Josephine
County, Oregon on land owned by The Nature Conservancy (Agate
Desert Preserve), Jackson County, Oregon Department of Fish and
Wildlife, City of Medford, Oregon Department of Transportation,
Bureau of Land Management (French Flat), and private landowners.
On lands managed by the U.S. Bureau of Reclamation, the Oregon Department of Transportation, the Oregon Department of Fish and Wildlife, and The Nature Conservancy, Cook’s lomatium receives protection from developmental related impacts. These agencies and organizations protect the species and manage their lands to benefit the species’ continued existence.
U.S. Fish and Wildlife Service. July 28, 2009. Endangered and Threatened Wildlife and Plants; Proposed Designation of Critical Habitat for Limnanthes floccosa ssp. grandiflora (Large-Flowered Woolly Meadowfoam) and Lomatium cookii (Cook’s Lomatium). Proposed Rule. Federal Register 74, No 143. U. S. Fish and Wildlife Service. Region 1. Portland, Oregon. pp. 37313 – 37392.