Spermodon eximius Nees in B. Seemann, Bot. Voy. Herald, 222. 1854; Psilocarya schiedeana (Nees) Liebmann; Rhynchospora oxycephala C. Wright; R. psilocaroides Grisebach

Plants perennial or annual, single or cespitose, (10–)20–50 cm; rhizomes absent. Culms spreading to erect, leafy, obtusely triangular. Leaves often exceeding inflorescences; blades narrowly linear, proximally flat, 1–3 mm wide, apex trigonous, tapering. Inflorescences terminal and axillary, clusters of 1–5 corymbs; leafy bracts much exceeding corymbs. Spikelets few to several, on ascending, stiff, short-to-elongate branches, red-brown to brown, lanceoloid, (5–)6–10 mm, apex acuminate; fertile scales many, ovate, shallowly convex, 5 mm, apex acuminate; midrib short-excurrent or not. Flowers: perianth absent. Fruits 1.5 mm; body dark brown to black, tumidly lenticular, nearly orbicular, 0.8–0.9 × 0.6–0.7 mm, margins grooved, discontinuous with tubercle; surfaces transversely wavy rugose, ridges of contiguous rows of vertical, linear, raised cells; tubercle broad, low triangular, 0.2–0.3 mm, crustaceous, base capping fruit summit, raised at ends, apex short acuminate.

Fruiting all year. Moist to wet sandy peaty swales, pond shores, depressions in savannas, moist waste areas; 0–100[–1000] m; Fla.; Mexico; West Indies; Central America; South America; Africa.

Rhynchospora eximia is often found at elevations from near sea level to over 1000 m in the tropics.