Plants annual, not rhizomatous, stoloniferous, or bulbiferous. Stems erect, branched, 1-10 cm. Leaves alternate, erect, not distinctly petiolate, with clasping leaf sheaths; blade linear, 5-50 × 0.5-2 mm. Inflorescences terminal, 1-bracteate; bract linear to oblanceolate, 1-6 mm. Flowers 4-12; sepals 1.5-2.5 mm; petals 5, white, 1.5-3 mm; stamens 3, anther yellow. Seeds 0.8-1.2 mm, tuberculate; elaiosome absent. 2n = 14. Flowering spring. Moist or transitional wetland habitat in coastal and inland valleys; 800-1600 m; B.C.; Calif., Idaho, Oreg., Wash.