Herbs, perennial, cespitose, floriferous culm 0.5--3 dm. Culms first ascending, soon arcuate-stoloniferous and creeping or floating, or growing submersed along bottom, each node with cluster of basal leaves and fibrous roots, eventually each emergent terrestrial node with floriferous culm. Leaves basal; auricles 0.5--1 mm, apex acutish, membranous or thicker; blade spreading, flat, 2--10(--15) cm x 1--3 mm. Inflorescences glomerules, (1--)2--10, each with 3--12 flowers, open; primary bract usually shorter than inflorescence. Flowers: tepals green, margins scarious; inner series narrowly lanceolate, 5--9 mm, apex usually recurved; outer series obviously shorter, apex usually erect; stamens 3, filaments 1.5--3 mm, anthers 0.5--0.8 mm; style 0.5 mm. Capsules tan, 3-locular, narrowly ellipsoid, 3.5--5.5 x 0.8--1.2 mm. Seeds brown, ovoid, 0.3--0.4 mm, not tailed. Flowering and fruiting summer--fall. Shores of ponds, lakes, and borrow pits, flatwood depressions, ditches, and drainage canals; Ala., Ark., Del., Fla., Ga., La., Md., Miss., N.C., Okla., S.C., Tenn., Tex., Va.; Mexico (Tabasco); West Indies (Cuba).
Stems at first erect or ascending, 5-20 cm, with numerous soft basal lvs, a few cauline lvs, and a terminal infl of 2-8 sessile or peduncled heads, each 8-15 mm thick and composed of 5-15 green, often falcately curved fls; stem later becoming elongate, prostrate or floating, and producing additional flowering branches from the nodes; fls eprophyllate; tep rigid, subulate, the sep 4-5 mm, the pet 5-10 mm; stamens 3; fr trilocular, slender, obtuse, about equaling or a little shorter than the sep. Wet shores, marshes, and shallow water, on the coastal plain; Del. to Fla., Tex., and Okla.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.