Plants 10-40 cm. Stems usually ascending to erect, sometimes prostrate. Leaves: stipules 6-9 mm; blade 1.5-5.5 cm. Flowers: sepal lobes ± lanceolate, 4.5-5.5 mm, to 6.5 mm in fruit; petals white, 1-1.1 times as long as sepals; styles 1.2-1.9 mm. Capsules 1.2-1.4 times as long as sepals. Seeds dark red-brown, not grooved, suborbiculate, 0.7-0.8 mm, smooth to faintly tuberculate (40×); wing absent or 0.1-0.3 mm wide. Flowering spring. Alkaline soils, floodplains, vernal pools, meadows, marshy ground; 0-800 m; Calif.