Plant: Annual, slender, ± hairy, taprooted; stem erect, 3-40 cm Leaves: opposite; petiole 2.5-3.5 cm; blade 2-6 cm, oblong to ovate, pinnately dissected, segments 2-8 mm, thread-like to linear INFLORESCENCE: umbels generally compound; peduncle 2-10 cm; bracts 2-5, leaf-like, pinnately lobed to compound, 1-5 cm; bractlets 1-5, 1-10 mm, entire or some often 3-lobed at tip or pinnately lobed; rays 1-9, 1-8 cm, unequal, erect or ascending; pedicels 2-9, < 15 mm, erect Flowers: many, minute, slightly bilateral; calyx lobes evident; petals obovate, white, tips narrowed; stamens 5; pistil 1, ovary inferior, 2-chambered, generally with a ± conic, persistent projection or platform on top subtending 2 free styles; styles very short Fruit: 2 dry, 1-seeded halves that separate from each other but generally remain attached for some time to a central axis, oblong, compressed side-to-side; primary ribs bristly, alternating with prickly wings; oil tubes per interval between primary ribs 1; fruit axis divided in upper ¼; Seed: face deeply grooved Misc: Grassy slopes, dunes, chaparral, woodland; 0-1500 m.