Plants perennial; cespitose or shortly rhizomatous. Culms 25-110 cm, erect, spreading, or prostrate; nodes glabrous or pubescent. Sheaths glabrous or pubescent; ligules 0.2-0.5 mm; blades flat, glabrous or pubescent. Panicles terminal and axillary, with 1-6 racemosely axillary arranged branches, panicles partially or completely enclosed by the subtending leaf-sheath; branches 2-12 (17) cm, ascending to spreading, often arcuate, terminating in a spikelet; branch axes 0.2-1.2 mm wide, glabrous, sometimes scabrous. Spikelets 1.4-2.6 mm long, paired, imbricate, appressed to the branch axes, elliptic to obovate to ovate to orbicular, stramineous or brown. Lower glumes absent; upper glumes and lower lemmas glabrous or shortly glandular-pubescent, 3-veined, margins entire; lower lemmas lacking ribs over the veins; upper florets stramineous. Caryopses elliptic to suborbicular, white. 2n = 20.

Distribution

Conn., N.J., N.Y., Va., Del., D.C., Wis., W.Va., Ont., Fla., N.H., N.Mex., Tex., La., Tenn., N.C., S.C., Pa., Mass., R.I., Vt., Puerto Rico, Colo., Md., Ala., Ark., Ill., Ga., Ind., Iowa, Ariz., Kans., Nebr., Okla., Ohio, Mo., Minn., Mich., Mont., Miss., Ky., S.Dak.

Discussion

Paspalum setaceum is a variable species that grows east of the Rocky Mountains in the contiguous United States and Mexico. The following treatment summarizes the major patterns of variation within the species. Some specimens will be hard to place, particularly old herbarium specimens that have lost their color. Nine varieties grow in the Flora region.

Selected References

None.

Key

1 Leaf blades conspicuously basal, recurved, 3-10 mm wide; lower lemmas without evident midveins. > 2
2 Leaf blades yellowish-green, usually glabrous; spikelets usually glabrous, not spotted Paspalum setaceum var. longepedunculatum
2 Leaf blades grayish-green, hirsute; spikelets short pubescent, often spotted Paspalum setaceum var. villosissimutn
1 Leaf blades more evenly distributed, lax to straight, 1.5-20 mm wide; lower lemmas with or without evident midveins. > 2
3 Leaf blades glabrous (or almost so) on the surfaces, sometimes ciliate on the margins. > 4
4 Leaf blades 2.4-6.1 mm wide, stiff; spikelets 2-2.6 mm long Paspalum setaceum var. rigidifolium
4 Leaf blades 3-18 mm wide, lax to somewhat stiff but, if somewhat stiff, more than 6 mm wide; spikelets 1.7-2.4 mm long. > 5
5 Lower lemmas without evident midveins; blades yellowish-green to dark green Paspalum setaceum var. stramineum
5 Lower lemmas with evident midveins; blades dark green to purplish Paspalum setaceum var. ciliatifolium
3 Leaf blades evidently hirsute on the surfaces as well as on the margins. > 4
6 Plants widely spreading to prostrate. > 7
7 Leaf blades grayish-green; lower lemmas without evident midveins Paspalum setaceum var. psammophilum
7 Leaf blades yellowish-green; lower lemmas with or without evident midveins Paspalum setaceum var. supinum
6 Plants erect to spreading. > 7
8 Lower lemmas usually with evident midveins; spikelets 1.8-2.5 mm long, usually glabrous, light green to green Paspalum setaceum var. muhlenbergii
3 Lower lemmas usually without evident midveins; spikelets 1.4-2.4 mm long, usually pubescent, pale yellow to light green. > 4
9 Leaves grayish-green; blades 1.5-7 mm wide, always conspicuously hirsute Paspalum setaceum var. setaceum
9 Leaves yellowish-green to dark green; blades 3.3-13.5 mm wide, almost glabrous or conspicuously hirsute Paspalum setaceum var. stramineum

"decumbent" is not a number."elongated" is not a number.

... more about "Paspalum setaceum"
anatomy +  and kranz +
Charles M. Allen +  and David W. Hall +
Michx. +
1 (?) +  and 3 (?) +
keeled +  and rounded +
pseudopetiolate +  and branching +
divergent +  and parallel +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
membranous +
disarticulating +  and pseudopetiolate +
non-radiate +  and radiate +
pubescent +  and glabrous +
usually linear +  and lanceolate occasionally ovate +
17 cm170 mm <br />0.17 m <br /> (?) +
0.2mm +  and 1.2mm +
ascending;spreading +
spikelike +
not developed +
ringlike +
elliptic +  and suborbicular +
sometimes longer +
branched +  and solid +
prostrate +, spreading +  and erect +
25 cm250 mm <br />0.25 m <br /> (110 cm1,100 mm <br />1.1 m <br />) +
Conn. +, N.J. +, N.Y. +, Va. +, Del. +, D.C. +, Wis. +, W.Va. +, Ont. +, Fla. +, N.H. +, N.Mex. +, Tex. +, La. +, Tenn. +, N.C. +, S.C. +, Pa. +, Mass. +, R.I. +, Vt. +, Puerto Rico +, Colo. +, Md. +, Ala. +, Ark. +, Ill. +, Ga. +, Ind. +, Iowa +, Ariz. +, Kans. +, Nebr. +, Okla. +, Ohio +, Mo. +, Minn. +, Mich. +, Mont. +, Miss. +, Ky. +  and S.Dak. +
capillary +
germination +
pistillate +  and staminate +
sometimes longer +
compressed +  and terete +
shorter or longer +
subtending +
unequal +
membranous +
uncinate +
bracteate +  and ebracteate +
solid +  and hollow +
cauline +  and basal +
coriaceous +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.05 cm0.5 mm <br />5.0e-4 m <br />) +
membranous +
inconspicuous +
complex +  and simple +
concealed +  and prominent +
pubescent +  and glabrous +
2 +  and 1 +
subterranean +
spreading +  and erect +
dry +  and fleshy +
pubescent +  and glabrous +
subsessile +  and shortly pedicellate +
imbricate +  and paired +
brown +  and stramineous +
0.14 cm1.4 mm <br />0.0014 m <br /> (0.26 cm2.6 mm <br />0.0026 m <br />) +
1 +  and 60 +
unisexual +  and bisexual +
elliptic +  and obovate +
1 (?) +  and 3 (?) +
fused +  and free +
2 (?) +  and 3 (?) +
dome--shaped +  and triangular +
Gramineae +
Paspalum setaceum +
Paspalum +
species +
membranous +
stipitate +  and sessile +
rounded +  and acute +
glandular-pubescent +  and glabrous +
stramineous +  and dark-brown +
smooth +  and slightly rugose +
glandular-pubescent +  and glabrous +
smooth +  and slightly rugose +
plant +  and cespitose +
aquatic +  and terrestrial +
dioecious +, monoecious +  and synoecious +