Plants 10-30 cm. Stems ascending or erect, sometimes prostrate. Leaves: stipules 4.5-8 mm; blade 1.5-4 cm. Flowers: sepal lobes ovate to lanceolate, (4.5-)5-5.5 mm, to 7 mm in fruit; petals white, 1-1.3 times as long as sepals; styles 2-3 mm. Capsules 0.8-1 times as long as sepals. Seeds dark red-brown, often with submarginal groove, sub-orbiculate to pyriform, 0.8-1.2 mm, covered with rounded, elongate tubercles; wing sometimes absent, 0.2-0.3 mm wide.

Flowering spring. Alkaline marshes, mud flats, meadows, hot springs; 20-200 m; Calif.