Plants annual or short-lived perennials flowering in the first year; cespitose,
not rhizomatous. Culms 7-35(60) cm, erect or decumbent. Sheaths
rounded below, margins and apices hairy, hairs to 3 mm; ligules 0.3-1 mm;
blades 2-12(20) cm long, 2-6 mm wide, flat, abaxial surface glabrous, adaxial
surface scabridulous, sometimes sparsely hispid, margins ciliate-pectinate. Panicles
4-15(18) cm long, 0.3-6 cm wide, open (contracted when immature), pyramidal; lower
nodes with 7-12(15) branches; primary branches 0.5-4.5 cm, spreading
30-90° from the rachis, with elongated glands, without spikelets on the lower
1/3-1/2; secondary branches appressed; pedicels 0.1-0.5 mm, appressed.
Spikelets 1.2-1.8 mm, plumbeous or brownish, often secund along the branch.
Glumes unequal, ovate to obovate, membranous; lower glumes 0.3-0.7
mm, without midveins; upper glumes 1.2-1.8 mm, at least 2/3 as long as
the florets, often longer; lemmas 1.2-1.7 mm, ovate to elliptic, membranous,
glabrous, acute; paleas 1.1-1.6 mm, ovate to elliptic, membranous, glabrous;
anthers 0.2-0.4 mm, yellowish or purplish. Fruits 0.6-1 mm, obovoid,
faintly striate, light brownish. 2n = 24, 36, 54.
Sporobolus pyramidatus is native to the Americas, extending from the southern
United States to Argentina. It grows in disturbed soils, roadsides, railways,
coastal sands, and alluvial slopes in many plant communities, at elevations from
0-1500 m. Morphologically, it is very similar to the Eastern Hemisphere S.
coromandelianus (Retz.) Kunth, suggesting that they are closely related.
Tufted perennial (often blooming the first year) 1-7 dm, usually ascending or prostrate; lvs crowded at base; sheaths pilose at the throat; blades flat, 5-20 cm נ2-4 mm, sparsely long-ciliate toward the base; panicle pale, pyramidal, 3-10(-20) נ1.5-6+ cm, the lower branches whorled, widely spreading, somewhat viscid, closely fld, naked toward the base; spikelets pale, 1.2-2 mm; first glume 0.3-1 mm, the second equaling the lemma; 2n=24, 36. Sandy or gravelly soil, along the seashore and in alkaline soil in the interior, sometimes a street-weed; trop. Amer., n. to Kans. and Mo., and as an adventive to N.Y. (S. argutus)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.