Herbs, annual, biennial, or perennial. Taproots slender. Stems erect to prostrate, branched, terete. Leaves connate proximally, sessile; blade 1-veined, subulate to linear, not succulent, apex acute or obtuse. Inflorescences terminal or axillary, lax to dense cymes; bracts paired, foliaceous. Flowers sessile to subsessile; perianth and androecium perigynous; hypanthium urceolate, abruptly expanded distally; sepals 5, distinct, greenish, lanceolate to awl-shaped, 1.5-4 mm, herbaceous, margins whitish, scarious, apex acute to blunt or obtuse; petals absent; nectariferous disc at base of stamens; stamens 2-10, arising from hypanthium rim; filaments distinct; staminodes absent or 5-8, arising from hypanthium rim, filiform; styles 2, capitate, 0.8-1 mm, glabrous proximally; stigmas 2, terminal, minutely papillate (50×). Utricles ovoid, enclosed in persistent, indurate, shallowly or strongly furrowed, sepal-crowned hypanthium and falling with it, the whole constituting the indehiscent 'fruit'; carpophore present. Seeds 1, yellowish, globose, not compressed, smooth, marginal wing absent, appendage absent. x = 11 [12].

Fls in compact, terminal and axillary cymose clusters, perfect, perigynous, the cupulate hypanthium resembling a cal-tube; sep 5; pet none; stamens 1-10; ovary ovoid; styles 2, distinct; ovule one on a basal placenta; hypanthium becoming indurate in fr, crowned by the persistent sep and enclosing the membranous utricle; seed obovoid, beaked at the micropylar end; low herbs with diffusely forking stems and opposite, exstipulate lvs connate at base. 10, Old World.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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