Plants perennial; cespitose, occasionally rhizomatous. Culms 40-130 (150) cm tall, 1-4 mm thick, frequently glaucous. Sheaths with sparsely hairy apices, hairs to 3 mm, not conspicuously tufted; uppermost sheaths 0.5-3 mm wide; ligules 0.1-0.4 mm; blades 4-23 cm long, 1.5-4 mm wide, flat or involute, abaxial surface glabrous or pilose, adaxial surface glabrous or scabridulous, margins glabrous. Panicles terminal and axillary, 5-11 cm long, 0.04-0.2 (0.3) cm wide, with 10-40 spikelets per cm2, narrow, sometimes spikelike, included in the uppermost sheath; lower nodes with 1-2 (3) branches; primary branches 0.4-5 cm, appressed, spikelet-bearing to the base; secondary branches appressed; pulvini glabrous; pedicels 0.3-3.5 mm, appressed, glabrous or scabridulous. Spikelets 4-9 (10) mm, stramineous to purplish-tinged. Glumes subequal, lanceolate, membranous to chartaceous, midveins usually greenish; lower glumes 1.5-6.2 mm; upper glumes (2) 2.5-5 (6.5) mm, slightly shorter or longer than the lemmas; lemmas (2.2) 3-7 (7.4) mm, lanceolate, chartaceous and opaque, minutely appressed-pubescent or scabridulous, occasionally 2-veined or 3-veined, acute to obtuse; paleas (2.2) 3-9 (10) mm, ovate to lanceolate, chartaceous; anthers 2.2-3.2 mm, yellow to orangish. Fruits (1.5) 2.4-3.5 mm, ellipsoid, laterally flattened, often striate, reddish-brown; pericarps loose, but neither gelatinous nor slipping from the seeds when wet. 2n = unknown.
Del., D.C., Wis., W.Va., Fla., N.J., Tex., La., Tenn., N.C., S.C., Pa., N.Y., Va., Ala., Ark., Ill., Ga., Ind., Iowa, Conn., Md., Kans., Okla., Mo., Miss., Ky., Mass.
Sporobolus clandestinus grows primarily in sandy soils along the coast and, inland, along roadsides. In the southeastern United States, it is found in dry to mesic longleaf pine-oak-grass communities and cedar glades. Its range lies entirely within the Flora region.
"decumbent" is not a number.