Plant: Plant 1.5-12 dm, annual, biennial, taprooted, hair, generally branched Leaves: petiole 3-10 cm; blade 5-15 cm, oblong, pinnately dissected; segments 2-12 mm, linear to lanceolate, acute, entire or with a few irregular cuts, bristly to glabrous INFLORESCENCE: umbels compound; peduncles 2.5-6 cm, bracts conspicuous, generally pinnately lobed; bractlets entire to toothed; bristles reflexed to spreading; rays 3-7.5 cm; pedicels 3-10 mm Flowers: many, small, outer sometimes ± bilateral; calyx lobes 0 or evident; petals wide, white, tips narrowed, unequally 2-lobed; stamens 5; pistil 1, ovary inferior, 2-chambered, generally with a ± conic, persistent projection or platform on top subtending 2 free styles Fruit: 2 dry, 1-seeded halves that separate from each other but generally remain attached for some time to a central axis, 3-4 mm, ovate, compressed front-to-back; ribs 10, primary thread-like and bristly, secondary winged and prickly; oil tubes 1 beneath each secondary ribs; fruit axis entire or notched at tip Misc: Roadsides, disturbed places; 0-1200 m.