63. Rhynchospora debilis Gale, Rhodora. 46: 194, plate 826, figs. 5A, B. 1944.
Rhynchospora fascicularis (Michaux) Vahl var. debilis (Gale) Kükenthal
Plants perennial, cespitose, 20–45 cm; rhizomes absent. Culms erect to arching or spreading, leafy, ± filiform, ± terete, stiff to rather lax. Leaves exceeded by culm; blades linear filiform, proximally shallowly concave, 1 mm, apex tapering, trigonous, blunt or broadly acute. Inflorescences: spikelet clusters 1–2, mostly compact, turbinate to hemispheric; leafy bracts setaceous, exceeding spikelet clusters. Spikelets dark red brown, ovoid, 2–3 mm, apex acute; fertile scales obovate, 1.5–1.7(–2) mm, apex broadly rounded or retuse, midrib excurrent as cusp or mucro to 0.5 mm. Flowers: bristles 6 or vestigial, rarely reaching fruit midbody, antrorsely barbellate. Fruits 1–2 per spikelet,1.7–2 mm; body brown with large pale center, lenticular, broadly obovoid to ± orbicular, 1.2–1.5 × 1.4–1.6 mm; tubercle flat, triangular, concave-sided, 0.4–0.6 mm, sometimes apiculate.
Fruiting late spring–fall. Sands and peats in low, open fields, bogs, seeps, low pinelands, savannas, and ditch banks; 0–200 m; Ala., Fla., Ga., La., Miss., N.C., S.C., Tex., Va.
Rhynchospora debilis is very similar to R. wrightiana except it has smaller spikelet clusters and more depressed fruit tubercles. It is a common invader of cutover and bulldozed low pineland where it assumes a low spreading habit, its many culms radiating from the common center much like spokes in a wheel.