Plants perennial; shortly rhizomatous. Culms 40-120 cm, erect; nodes
glabrous or pubescent. Sheaths glabrous or pubescent; ligules 1.5-3.8
mm; blades to 37 cm long, 2-9.3 mm wide, flat, glabrous or pubescent. Panicles
terminal, with 1-6 racemosely arranged branches; branches 2-10.9 cm, diverging
to spreading (rarely erect), persistent; branch axes 0.6-1.3 mm wide, glabrous,
margins scabrous, terminating in a spikelet. Spikelets 2.3-3.3 mm long,
2-2.7 mm wide, solitary, appressed to the branch axes, elliptic to obovate or
nearly orbicular, glabrous, stramineous. Lower glumes absent; upper
glumes 3-veined, lower lemmas 5-veined; upper florets pale to
stramineous. Caryopses about 2 mm, white to yellow-brown. 2n = 20,
58, 70, 80.
Paspalum laeve is restricted to the eastern United States. It grows at
the edges of forests and in disturbed areas.
Perennial herb with short rhizomes 40 cm - 1.2 m tall Leaves: alternate, two-ranked. Sheaths open, sometimes hairy. Ligules 1.5 - 4 mm long, membranous. Blades to 37 cm long, 2 - 9 mm wide, lance-shaped, flat, parallel-veined, sometimes hairy. Inflorescence: a terminal, branched arrangement of spikelets (panicle), bearing one to six branches. Branches spreading to diverging, 2 - 11 cm long, spike-like, with spikelets mostly arranged in two rows along one side of the branch. Branch axes 0.5 - 1.5 mm wide and rough along the margins. Fruit: a caryopsis, indehiscent, enclosed within the persistent lemma and palea, white to yellowish brown, about 2 mm long, orbicular to elliptical. Culm: prostrate or spreading, 40 cm - 1.2 m long, round in cross-section, hollow. Nodes sometimes hairy. Spikelets: solitary, arranged in two rows along one side of the inflorescence branch, appressed to the branch axis, bearing two florets, straw-colored, 2 - 3.5 mm long, 2 - 2.5 mm long, plano-convex (one side flat, the other convex), nearly orbicular to elliptic or reverse egg-shaped. Glumes:: Lower glumes absent. Upper glumes nearly equal to lower lemmas, rounded at the apex, three-veined, membranous. Lemmas:: Lower lemmas nearly equal to upper glumes, rounded at the apex, five-veined, membranous. Upper lemmas clasping the paleas, straw-colored to brown, convex, smooth to slightly wrinkled, with rolled-up margins on the upper surface. Paleas:: Lower paleas rudimentary or absent. Upper paleas straw-colored to brown, smooth to slightly wrinkled. Florets:: Lower florets sterile. Upper florets bisexual, pale to straw-colored. Anthers three. Stigmas red.
Similar species: No information at this time.
Flowering: late July to mid-September
Habitat and ecology: Probably introduced into the Chicago Region from farther south. It is a rare species found along railroads and in sandy disturbed ground.
Occurence in the Chicago region: non-native
Etymology: Paspalum comes from the Greek word paspalos, a type of millet. Laeve means smooth.
Culms erect or ascending, 3-8 dm, usually several from one base; sheaths keeled, usually loose, villous to pilose or glabrous; blades 5-25 cm נ3-10 mm, glabrous or pilose; racemes 2-6, spreading, 4-12 cm; spikelets borne singly, glabrous, planoconvex, obovate to elliptic, orbicular, or obovate, 2.4-3.4 mm, two-thirds to fully as wide; glume and sterile lemma 5-veined, the outer veins approximate near the margin; 2n=40, 80. Various habitats; se. Mass. to Pa., O., s. Ind., Mo. and Kans., s. to the Gulf. Abundant and variable. (P. angustifolium; P. circulare; P. longipilum; P. plenipilum)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.