Herbs, annual or perennial, caudices often branched. Taproots slender, elongate. Stems sprawling to erect, simple or branching proximally or throughout, terete. Leaves opposite or appearing whorled, connate by membranous to thickened line, petiolate or sessile, stipulate (D. pachyphylla not stipulate); stipules 2 per node, white to tan, simple or divided into segments, subulate to filiform, often minute, margins entire, apex acute to acuminate; blade 1-5-veined, linear to lanceolate, spatulate, ovate, reniform, or orbiculate, not succulent, apex rounded to acuminate. Inflorescences terminal or axillary, open to congested, bracteate cymes or umbelliform clusters or flowers solitary, axillary; bracts paired, scarious or central portion herbaceous. Pedicels erect to spreading or reflexed. Flowers: perianth and androecium hypogynous; sepals 5, distinct, white, lanceolate to oblong, ovate, or orbiculate, 1.5-4.8(-5) mm, herbaceous, margins white to purple, scarious, apex acuminate to rounded, hooded or not; petals (3-)5, sometimes absent, white, claw narrow, tapering distally or with oblong or expanded, sessile or short-clawed trunk, auricles absent, blade apex divided into 2 or 4 lobes; nectaries at base of filaments opposite sepals; stamens 5; filaments distinct or briefly connate proximally; styles 3, occasionally 2, connate proximally for 2 of length, rarely to nearly distinct (D. cordata), filiform, 0.1-0.3 mm, glabrous proximally; stigmas 3, occasionally 2, linear along adaxial surfaces of styles (or branches), obscurely papillate (30×). Capsules ellipsoid to globose, opening by (2-)3 spreading to recurved valves; carpophore absent. Seeds 3-25, tan, reddish brown, dark brown, black, or transparent (white embryo visible), horseshoe-, snail-shell- or teardrop-shaped, compressed laterally, at least somewhat, tuberculate, marginal wing absent, appendage absent. x = (11), 12.