Distribution: Endemic in Klickitat County, Washington
Habitat: Dry, open slopes
Conservation Status: Sensitive in Washington (WANHP)
Stout, glabrous perennial from a taproot and branching woody base, 5-20 dm. tall.
Leaves large, basal and cauline, ternate-pinnately dissected into long, narrow, acute ultimate segments, 1-5 cm. long and 1-5 mm. wide; the first umbel of the season is sterile and sometimes borne on a leafless stem.
Inflorescence of compound umbels, the rays 6-11 cm. long at maturity; involucre none; involucel of well-developed bractlets about 1 cm. long; calyx teeth none; flowers yellow; pedicels 6-13 mm. long.
Fruit very large, elliptic, 15-32 mm. long, the lateral wings 1/3 to as wide as the body; dorsal ribs raised.