Plants 0.3-2.1 dm. Stems erect to decumbent. Leaves 2-30(-40) mm; basal with blade spatulate; proximal cauline whorled, blade linear-spatulate; distal opposite or whorled, blade broadly linear to ovate; petiole to 3 cm; margins entire or occasionally denticulate. Inflorescences: peduncle 1.5-5 cm. Flowers: receptacle ± as long as broad, not expanded into ring beneath calyx; petals white, occasionally with obscure yellowish green patch near base, narrowly ovate, nearly equal, 2-6 × 1-2 mm, apex rounded; stamens 6 in 1 series; filaments ± equal, nearly as broad as anthers, tapering from base; anthers linear-oblong, usually at least 1/2 length of filaments. Capsules to 30 × 2.5 mm. 2n = 16.
Phenology: Flowering early–late spring.
Habitat: Moist, partly shaded slopes in chaparral or oak-pine woodlands
Elevation: 100-1000 m
Plants from the southern end of the range tend to have longer anthers and shorter filaments.