Rhynchospora axillaris (Lamarck) Britton var. microcephala Britton, Trans. New York Acad. Sci. 11: 89. 1892 (as Rynchospora); R. cephalantha A. Gray var. microcephala (Britton) Kükenthal

Plants perennial, cespitose, 30–90 cm; rhizomes absent. Culms arching or erect, leafy, nearly terete, multiribbed, slender. Principal leaves overtopped by culm; blades linear, proximally flattened, 1–3 mm wide, apex tapering, trigonous. Inflorescences: spikelet clusters 2–6, mostly widely spaced; clusters dense, hemispheric to mostly spheroid, 0.5–1 cm thick. Spikelets dark red brown to dark brown, lance ovoid, (2–)2.5–3.5(–4) mm, apex acute; fertile scales elliptic, 2–3 mm, apex acute, midrib short excurrent or not. Flowers: perianth bristles 6, reaching tubercle tip, retrorsely barbellate. Fruits 1 per spikelet, 2.5–3 mm; body pale brown with light center, lenticular, obovoid distal to stipe, 1.1–1.5 × 0.9–1.1 mm, margins pale, wirelike, surfaces slick; tubercle triangular subulate, 0.9–1.2(–1.5) mm, at least 0.5 mm wide at base.

Fruiting summer–fall. Sands and sandy peats of savanna swales, pineland seeps, bogs, ditches, pond shores and banks; 0–200 m; Ala., Del., D.C., Fla., Ga., La., Md., Miss., N.J., N.C., S.C., Va.; West Indies (Cuba).