Plants annual, autotrophic, at least partly green. Rhizomes absent. Roots filiform. Stems usually unbranched, green. Leaves cauline, sometimes basal, green, purplish, or pale, scalelike to linear. Inflorescences 2-25-flowered cymes or flowers solitary; floral bracts sometimes appearing imbricate if internodes of cyme rachis are very short; pedicels 0-1 mm. Flowers erect, 3-ribbed to 3-winged; perianth persistent in fruit; annulus absent; stamens 3, proximal to inner perianth lobes, sessile; ovary 3-locular; placentation axile. Capsules obovoid to ellipsoid, transversely dehiscent.