Page authors: Don Knoke, David Giblin
Lomatium ambiguum
streambank desert-parsley, swale desert-parsley, lacy lomatium
WTU specimens
Other herbaria

Distribution: Chiefly east of the Cascades in Washington; southern British Columbia south to northeast Oregon, east to western Montana.

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

Flowers: May-July

Origin: Native

Conservation Status: Not of concern


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

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.

E-Flora BC: Lomatium ambiguum atlas page.

CalPhotos: Lomatium ambiguum photos.

USDA Plants: Lomatium ambiguum information.

35 photographs:
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