Fimbristylis melanospora Fernald; F. obtusifolia (Lamarck) Kunth 1837, not Nees ex C. Presl 1828; F. sintenisii Boeckeler; F. spathacea Roth; Scirpus obtusifolius Lamarck

Plants perennial, cespitose, (5–)10–60 cm, bases hard, glabrous; rhizomes absent. Leaves polystichous, mostly spreading-excurved, to 1/2 as long as culms; sheaths usually entire; ligule absent; blades linear, 2–3 mm wide, flat or shallowly involute, margin scabrid, apex blunt. Inflorescences: simple or compound anthelae with numerous small pedunculate clusters of sessile spikelets; scapes linear, distally terete, 1–2 mm thick; involucral bracts short, usually shorter than inflorescence. Spikelets greenish brown or yellow-brown, ovoid, 2–3 mm; fertile scales broadly ovate, 1–1.5 mm, obtuse or apically notched, midrib not excurrent. Flowers: stamens usually 1; styles 2-fid, slender, glabrous. Achenes dark brown to nearly black, tumidly obovoid, rarely obscurely 3-ribbed, 1 mm, faintly striate to variously warty, faintly reticulate. 2n = 56.

Fruiting all year. Sands of sea beaches, brackish sandy open sites, often disturbed, commonly just in from mangrove or on sandy road shoulders; 0–50 m; Fla.; s Mexico; Central America; South America; Africa; Asia; Indian Ocean Islands; Pacific Islands; Australia.

New World examples of Fimbristylis cymosa are almost exclusively bicarpellate, with bifid styles; Old World Oceania examples are tricarpellate, with trifid styles, a form not covered in this treatment.