Plants perennial, densely cespitose, 30-50(-70) cm; rhizomes absent. Culms erect to excurved, filiform, leafy, stiff to lax. Leaves mostly slightly exceeded by culm; blades ± filiform, proximally flat to concave, distally tapering, to 1 mm wide, margins involute, apex trigonous, subulate. Inflorescences terminal; spikelet clusters 1(-2), dense, broadly turbinate to hemispheric; longer leafy bracts 1-2(-several), setaceous, overtopping inflorescence. Spikelets light brown, narrowly ovoid, 2-2.5(-3) mm, apex acute or acuminate; fertile scales 1.5-2(-2.5) mm, apex acute, midrib excurrent as cusp or awn 0.5-0.9 mm. Flowers: bristles absent, rarely reduced to nubbins, or rarely 1, then shorter than fruit body. Fruits 1 per spikelet, 1-1.8 mm; body with dark brown ends, broad pale midzone, lenticular, ± orbicular, 1-1.2 × 0.8-1 mm, surfaces smooth; margins sharp, flowing to tubercle; tubercle low triangular, 0.2-0.3(-0.5) mm, sometimes apiculate.

Fruiting summer-fall; 0-200 m; Ala., Fla., Ga., La., Miss., N.C., S.C.

Rhynchospora chapmanii is a frequent invader of logged or otherwise disturbed pine savannas, often an aspect dominant. Its pale inflorescences are conspicuous masses in autumn.