Plants perennial, cespitose, to 150 cm; rhizomes stoloniferous, slender. Culms lax, leafy, wandlike, ± terete to obscurely angled, slender. Leaves ascending, exceeded by culms; blades flat, 4-7(-10) mm wide, apex trigonous, short acuminate, tapering. Inflorescences: spikelet clusters 4-6 or more, equidistant along culm on ascending peduncles, branches capillary, divaricate, clusters loose, diffuse, rounded. Spikelets light brown, ellipsoid to lanceoloid or ovoid, 2.5-3.5 mm, apex acute; fertile scales ovate, (1.5-)2-3 mm, apex rounded or acute, midrib forming apiculus. Flowers: perianth bristles 6, longest exceeding tubercle, antrorsely barbellate. Fruits 2-several per spikelet, 1.3-1.5 mm; body pale brown, broadly obovoid, tumidly biconvex, 1.1-1.2 × 1-1.1 mm; surfaces transversely sharply wavy rugulose, intervals with vertical, rectangular, shallow alveolae; tubercle depressed conic, slightly compressed, 0.2-0.3(-0.4) mm, edges setulose. Fruiting summer-fall. Sandy alluvium of swamp forests and gallery forests, low clearings forests; 0-400 m; Ala., Fla., Ga., La., Miss., N.C., S.C., Tex., Va.; West Indies. The ultimate branches in Rhynchospora miliacea typically terminate in only one or two spikelets, the scales of which fall quickly, and the exposed fruits look like short miniature strings of beads.
Stout, erect, commonly 1 m or more, loosely rhizomatous, with 1-few stems together; lvs numerous, flat, to 1 cm wide; infl of 4-8 often overlapping cymes, each decompound, with much elongate, widely divaricate or even reflexed, capillary branches, each terminating in a single ovoid spikelet 3-4 mm, the scales soon falling and exposing the 3-10 persistent achenes; bristles 6, fragile, antrorsely barbellate, surpassing the tubercle; achenes pale brown, obovate, 0.9-1.2 mm, nearly or quite as wide, transversely ridged; tubercle depressed-conic, 0.2-0.3 mm. Swamps on the coastal plain; se. Va. to Fla., La., and the W.I.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.