Distribution: Occurring on both sides of the Cascades crest in Washington and in the Columbia River Gorge. British Columbia to Baja California, east to Idaho, Utah, and New Mexico.
Habitat: Along streams, open woodlands, and vernally moist slopes at low elevations.
Conservation Status: Not of concern
Slender annual 1-4 dm. tall, simple or branched below, with stiff, spreading hairs throughout.
Leaves alternate, petiolate, mostly cauline, the blade 2-6 cm. long and 2-5 cm. wide, two or three times pinnately dissected into small, narrow ultimate segments.
Inflorescence of compound umbels, the rays of the primary umbels 1-9, 1-8 cm. long, ascending; the pedicels of the ultimate umbels short and unequal; involucre of several well-developed leaves; involucel of several entire or pinnatifid bractlets; calyx teeth 5; petals 5, white, obovate; styles 2, short.
Fruit oblong, 3-7 mm. long, with hooked prickles along the ribs, those of alternate ribs larger.