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- 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.
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.
Much like no. 7 [Sporobolus asper (P. Beauv.) Kunth]; perennial, occasionally rhizomatous, with solitary or tufted culms 4-17 dm; lower sheaths frequently pubescent, the collar usually pubescent but only rarely pilose; lvs often hairy, lemma (2.5-)3-7 mm, pubescent; palea pubescent, equaling to sometimes much surpassing the lemma; pericarp becoming loose when wet, but not gelatinous; 2n=46, 48, 52, 54, 56. Dry sandy soil and prairies; Tex. to Fla., n. to Kans., Io., s. Wis., Ind., Va., and near the coast to Mass. (S. asper var. c.; S. canovirens)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.