Sphenopholis pensylvanica

(L.) Hitchc.
Common names: Swamp oats
Endemic
Synonyms: Trisetum pensylvanicum (L.) P. Beauv.
Treatment appears in FNA Volume 24. Treatment on page 621.

Culms 30-120 cm, glabrous. Sheaths glabrous or pubescent; ligules 0.2-1 mm; blades 4-10 (20) cm long, (1) 2-8 mm wide, flat to slightly involute, smooth or scabridulous, sometimes pubescent. Panicles 7-35 cm long, 2-10 cm wide, erect to nodding, with relatively few, loosely arranged spikelets. Spikelets 4.5-9.5 mm. Lower glumes about 1/2 as wide as the upper glumes; upper glumes 3.6-6.2 mm, elliptical to oblanceolate, width/length ratio 0.15-0.28, apices acuminate to acute; lowest lemmas 3.5-6 mm, mostly smooth, apices scabridulous, unawned or awned, awns to 2.5 mm; distal lemmas scabrous, awned, awns 3-9 mm, slightly to evidently bent; anthers 0.5-1.8 mm. 2n = 14.

Distribution

Del., W.Va., Fla., N.J., Conn., Mass., R.I., La., Tenn., N.C., S.C., Pa., N.Y., Va., Ala., Ga., Md., Ohio, Mo., Miss., Ky.

Discussion

Sphenopholis pensylvanica grows in springheads, seepage areas, swamps, marshes, and other moist to wet places, at 0-1100 m, in the eastern and southeastern United States. It hybridizes with S. obtusata (see below). The hybrids, which are called Sphenopholis xpallens (Biehler) Scribn., differ from S. pensylvanica in having generally shorter (3-5 mm) spikelets and shorter (0.1-4 mm), straight or bent awns on the distal lemmas. They differ from S. obtusata in having awns on the distal lemmas.

Selected References

None.

Lower Taxa

None.

"decumbent" is not a number.

... more about "Sphenopholis pensylvanica"
membranous +  and scarious +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.18 cm1.8 mm <br />0.0018 m <br />) +
scabridulous +
acuminate +  and acute +
Thomas F. Daniel +
(L.) Hitchc. +
1 (?) +  and 3 (?) +
straight +
basal +  and terminal +
0.3 cm3 mm <br />0.003 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
keeled +  and rounded +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
4 cm40 mm <br />0.04 m <br /> (10 cm100 mm <br />0.1 m <br />) +
not evident +
scabridulous +  and smooth +
flat +  and slightly involute +
0.2 cm2 mm <br />0.002 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
spikelike +
Swamp oats +
not branching +
ascending +  and erect +
30 cm300 mm <br />0.3 m <br /> (120 cm1,200 mm <br />1.2 m <br />) +
not woody +
Del. +, W.Va. +, Fla. +, N.J. +, Conn. +, Mass. +, R.I. +, La. +, Tenn. +, N.C. +, S.C. +, Pa. +, N.Y. +, Va. +, Ala. +, Ga. +, Md. +, Ohio +, Mo. +, Miss. +  and Ky. +
1/4 +  and 1/3 +
capillary +
pistillate +  and staminate +
sometimes longer +
2 +  and 3 +
sterile +  and bisexual +
compressed +
reduced +
shorter or longer +
subtending +
unequal +
membranous +  and subcoriaceous +
uncinate +
distributed +
keeled +  and rounded +
not indurate +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
membranous +
inconspicuous +
entire +  and toothed +
0.35 cm3.5 mm <br />0.0035 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
concealed +  and prominent +
2 +  and 1 +
well-developed +
2-keeled +
7cm +  and 35cm +
erect +  and nodding +
spikelike +
2 cm20 mm <br />0.02 m <br /> (10 cm100 mm <br />0.1 m <br />) +
dry +  and fleshy +
pubescent +  and glabrous +
pubescent +  and glabrous +
compressed +
0.45 cm4.5 mm <br />0.0045 m <br /> (0.95 cm9.5 mm <br />0.0095 m <br />) +
1 +  and 3 +
simple +  and compound +
2 (?) +  and 3 (?) +
Trisetum pensylvanicum +
Sphenopholis pensylvanica +
Sphenopholis +
species +
membranous +
0.15 +  and 0.28 +
elliptical +  and oblanceolate +
0.36 cm3.6 mm <br />0.0036 m <br /> (0.62 cm6.2 mm <br />0.0062 m <br />) +
parallel +  and converging +
stoloniferous +  and rhizomatous +
plant +  and cespitose +
aquatic +  and terrestrial +