Page authors: Don Knoke, David Giblin
Lomatium ambiguum
Wyeth biscuit-root, stream bank desert-parsley, swale desert-parsley, lacy lomatium

Distribution: Occurring chiefly east of the Cascades crest in Washington; southern British Columbia to northeast Oregon, east to southeastern Alberta, western Montana, and Wyoming.

Habitat: Open, often rocky slopes and flats, from the foothills to middle elevations in the mountains.

Flowers: May-July

Origin: Native

Growth Duration: Biennial, Perennial

Conservation Status: Not of concern

Pollination: Bees, flies, butterflies, beetles, wasps


Usually branched, glabrous perennial from a taproot, 1-8 dm. tall.


Leaves basal and cauline or all cauline, ternately or ternate-pinnately 2-several times divided into narrow, unequal ultimate segments, the longer segments 1-8 cm. long and up to 5 mm. wide, the smallest ones only 1-2 mm. long. Taproot short and tuberous-thickened or long and slender, occasionally with 2 or more enlarged sections.


Inflorescence a compound umbel, the rays 3-10 cm. long; involucre and involucel wanting; calyx teeth obsolete, flowers yellow; pedicels 4-13 mm. long.


Fruit glabrous, narrowly oblong, 5.5-12 mm. long and 1.5-3.3 mm. wide; the wings evident but narrow, 0.3-0.5 mm. wide.

Accepted Name:
Lomatium ambiguum (Nutt.) J.M. Coult. & Rose
Publication: Contr. U.S. Natl. Herb. 7(1): 212. 1900.

Synonyms & Misapplications:
Cogswellia ambigua (Nutt.) M.E. Jones [IMF]
Peucedanum ambiguum (Nutt.) Nutt. ex Torr. & A. Gray
Additional Resources:

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

WA Flora Checklist: Lomatium ambiguum checklist entry.

OregonFlora: Lomatium ambiguum information.

E-Flora BC: Lomatium ambiguum atlas page.

CalPhotos: Lomatium ambiguum photos.

USDA Plants: Lomatium ambiguum information.

42 photographs:
Group by