Plants perennial; rhizomatous. Culms 25-100 cm, erect. Leavesbasal and cauline; sheaths glabrous, margins scarious, sparsely ciliate distally; ligules 0.5-1 mm, of hairs; blades flat to conduplicate, glabrous or scabrous. Panicles 10-30 cm; branches 5-15, 1-3.7 cm, erect, with more than 12 spikelets; terminal bristles 2.5-4 mm. Spikelets 2.2-3.2 mm, clearly overlapping. Lower glumes 0.8-1.2 mm, 1-3-veined, truncate; upper glumes and lower lemmas 2-2.4 mm, glabrous, 5-7-veined, acuminate; lower paleas 2-2.4 mm, scarious; upper lemmas and paleas 2-2.3 mm, rugose, stramineous to light brown, lemma margins scarious, inrolled, clasping the paleas, lemma apices acuminate; anthers 1.2-1.5 mm. Caryopses about 1 mm in diameter, spheroidal, slightly flattened, yellow. 2n = 18, 54.

Paspalidium geminatum grows in moist to wet, fresh to brackish areas. It is native to southeastern North America, the West Indies, and tropical regions of the Americas.