Page authors: Don Knoke, David Giblin
Lomatium cous
cous biscuit-root, cous, cous-root desert-parsley

Distribution: Occurring east of the Cascades crest in the southeastern counties in Washington; southeastern Washington to northeast Nevada, east to Montana and Wyoming.

Habitat: Dry, open, often rocky places often with sagebrush; common at low elevations, occasionally found at higher elevations.

Flowers: April-July

Origin: Native

Growth Duration: Perennial

Conservation Status: Not of concern

Pollination: Bees, flies, butterflies, beetles, wasps


Glabrous or short-hairy, glaucous perennial from a taproot, usually acaulescent, 1-3.5 dm. tall at maturity.


Leaves pinnately dissected, the ultimate segments varying from short, crowded and broad to longer and narrower, up to 15 mm. long and 3 mm. wide; leaves usually all basal, but there may be one or more cauline leaves. The taproot is usually short and tuberous-thickened, but occasionally more slender and elongate.


Inflorescence a compound umbel, the rays 5-20, unequal, 1.5-10 cm. long at maturity; involucre none; involucel bractlets well-developed, broadly oblanceolate to obovate, 2-5 mm. long, entire or few-toothed, often purplish; calyx teeth obsolete, flowers yellow; pedicels short, 1-3 mm. long.


Fruit oblong to broadly elliptic, 5-12 mm. long and 3-5 mm. wide, often roughened; lateral wings about equaling the body; dorsal wings sometimes present.

Accepted Name:
Lomatium cous (S. Watson) J.M. Coult. & Rose
Publication: Contr. U.S. Natl. Herb. 7(1): 214. 1900.

Synonyms & Misapplications:
Lomatium circumdatum (S. Watson) J.M. Coult. & Rose
Lomatium montanum J.M. Coult. & Rose
Additional Resources:

PNW Herbaria: Specimen records of Lomatium cous in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Lomatium cous checklist entry.

OregonFlora: Lomatium cous information.

E-Flora BC: Lomatium cous atlas page.

CalPhotos: Lomatium cous photos.

USDA Plants: Lomatium cous information.

53 photographs:
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