Plants 0.3-1.8 dm. Stems erect to ascending. Leaves 3-25 mm; basal with blade spatulate; proximal cauline whorled, blade linear-spatulate; distal usually opposite, blade broadly linear; petiole to 17 mm; margins entire or rarely denticulate. Inflorescences: peduncle 3-8 cm. Flowers: receptacle shorter than broad, expanded into small ring beneath calyx; petals white to cream colored or outer sometimes yellow, alternately obovate and narrowly ovate, 2-7 × 1-5 mm, apex rounded; stamens ca. (6-)12, in 2 series; outer filaments shorter than inner; anthers ovoid to globose, much shorter than filaments, usually broader. Capsules to 50 × 1.5 mm. 2 n = 16.

Flowering late winter-late spring. Moist, sunny slopes in open grassy areas in grasslands, oak or pine woodlands; 0-1000 m; Calif.

The yellow color that occurs in the outer petals of some plants fades at night and returns in daylight.