Dichanthelium oligosanthes

(Schult.) Gould
Common names: Few-flowered panicgrass
Synonyms: Panicum oligosanthes
Treatment appears in FNA Volume 25. Treatment on page 419.

Plants cespitose, with caudices. Basal rosettes well-differentiated; blades 2-6 cm, few, ovate to lanceolate. Culms 20-75 cm, geniculate basally, stiffly erect distally; nodes glabrous or sparsely pubescent; internodes often purplish, glabrous, puberulent, or papillose-hirsute; fall phase branching from the midculm nodes, branches initially ascending to erect, sometimes developing simultaneously with and overtopping the primary panicles, later rebranching to form short, bushy clumps of blades and small, included secondary panicles. Cauline leaves 5-7; sheaths not overlapping, glabrous, puberulent, or ascending papillose-hispid, margins ciliate, collars loose, puberulent; ligules 1-3 mm, of hairs; blades 5-12 cm long, 4-15 mm wide, flat or partly involute, glabrous or pubescent abaxially, with 7-9 major veins only slightly more prominent than the minor veins, bases ciliate, rounded to truncate, margins cartilaginous. Primary panicles 5-9 cm long, 3-6 cm wide, partly enclosed to long-exserted, with 6-60 spikelets; branches stiff or wiry, puberulent or scabridulous. Spikelets 2.7-4.2 mm long, 1.7-2.4 mm wide, ellipsoid to broadly obovoid, turgid, glabrous or sparsely pubescent. Lower glumes 1-1.6 mm, acute, similar in texture and vein prominence to the upper glumes; upper glumes strongly veined, often orange to purplish at the base; lower florets sterile; upper florets with minutely umbonate apices. 2n = 18.

Distribution

Wash., Va., Alta., B.C., Man., Ont., Sask., Del., D.C., Wis., W.Va., Fla., Wyo., N.H., N.J., N.Mex., Tex., La., Tenn., N.C., S.C., Pa., Okla., N.Y., Maine, Colo., Calif., Ala., Kans., N.Dak., Nebr., S.Dak., Ark., Vt., Ill., Ga., Ind., Iowa, Ariz., Idaho, Conn., Md., Mass., Ohio, Utah, Mo., Minn., Mich., R.I., Mont., Miss., Ky., Oreg.

Discussion

Dichanthelium oligosanthes grows throughout the southern portion of the Flora region and extends into northern Mexico. The primary panicles are briefly open-pollinated, then cleistogamous, from late May to early June; the secondary panicles, which are produced from June to November, are cleistogamous. The subspecies intergrade in areas of overlapping range, but they are usually distinct elsewhere.

Specimens of Dichanthelium oligosanthes that have few elongated internodes, but those elongated more than usual, are often mistaken for D. wilcoxianum. Unlike that species, however, they have turgid spikelets with an orange spot at the base of the lemma, indicating that they belong to D. oligosanthes. Such specimens seem to be most common among collections made in the southern and southwestern states during November, February, or March.

Sterile hybrids with Dichanthelium acuminatum have often been called Panicum scoparioid.es Ashe. Apparent hybrids with D. malacophyllum, D. ovale, and D. acuminatum subsp. columbianum are occasionally found.

Selected References

None.

Key

1 Spikelets ellipsoid to oblong-obovoid, usually 3.4-4.2 mm long, 1.7-2 mm wide, usually sparsely pubescent; blades usually 4-9 mm wide, more than 10 times longer than wide, often partly imolute; ligules 2-3 mm Dichanthelium oligosanthes subsp. oligosanthes
1 Spikelets broadly obovoid-ellipsoid, 2.7-3.5 mm long, 2-2.4 mm wide, usually glabrous; blades usually 6-15 mm wide, less than 10 times longer than wide, flat; ligules 1-1.5 mm long Dichanthelium oligosanthes subsp. scribnerianum

"usually distinctly longer and narrower" is not a number."decumbent" is not a number.

umbonate +
anatomy +  and kranz +
Mary E. Barkworth +
(Schult.) Gould +
1 (?) +  and 3 (?) +
keeled +  and rounded +
well-differentiated +
pseudopetiolate +  and branching +
divergent +  and parallel +
purplish spot +  and orange +
intravaginal +, extravaginal +, branching +  and basal +
rounded +  and truncate +
swelling +
disarticulating +  and pseudopetiolate +
non-radiate +  and radiate +
distinct +
5 cm50 mm <br />0.05 m <br /> (12 cm120 mm <br />0.12 m <br />) +
more prominent +
pubescent +  and glabrous +
involute +, flat +, ovate +  and lanceolate +
2 cm20 mm <br />0.02 m <br /> (6 cm60 mm <br />0.06 m <br />) +
0.4 cm4 mm <br />0.004 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
wiry +  and rebranching +
initially ascending;erect +
scabridulous +
spikelike +
0 cm0 mm <br />0 m <br /> (1 cm10 mm <br />0.01 m <br />) +
not developed +
terete +  and compressed +
sometimes longer +
Few-flowered panicgrass +
decumbent +  and sprawling +
geniculate +
20 cm200 mm <br />0.2 m <br /> (75 cm750 mm <br />0.75 m <br />) +
Wash. +, Va. +, Alta. +, B.C. +, Man. +, Ont. +, Sask. +, Del. +, D.C. +, Wis. +, W.Va. +, Fla. +, Wyo. +, N.H. +, N.J. +, N.Mex. +, Tex. +, La. +, Tenn. +, N.C. +, S.C. +, Pa. +, Okla. +, N.Y. +, Maine +, Colo. +, Calif. +, Ala. +, Kans. +, N.Dak. +, Nebr. +, S.Dak. +, Ark. +, Vt. +, Ill. +, Ga. +, Ind. +, Iowa +, Ariz. +, Idaho +, Conn. +, Md. +, Mass. +, Ohio +, Utah +, Mo. +, Minn. +, Mich. +, R.I. +, Mont. +, Miss. +, Ky. +  and Oreg. +
capillary +
germination +
pistillate +  and staminate +
sometimes longer +
compressed +  and terete +
shorter or longer +
subtending +
unequal +
membranous +
papillose-based +
uncinate +
0.1 cm1 mm <br />0.001 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
Oval (?) +  and Round (?) +
bracteate +  and ebracteate +
papillose-hirsute +, puberulent +  and glabrous +
cauline +  and basal +
coriaceous +
0.1 cm1 mm <br />0.001 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
membranous +
inconspicuous +
1/5 +  and 3/4 +
0.1 cm1 mm <br />0.001 m <br /> (0.16 cm1.6 mm <br />0.0016 m <br />) +
complex +  and simple +
concealed +  and prominent +
pubescent +  and glabrous +
2 +  and 1 +
subterranean +
dry +  and fleshy +
5 cm50 mm <br />0.05 m <br /> (9 cm90 mm <br />0.09 m <br />) +
partly enclosed +  and long-exserted +
3 cm30 mm <br />0.03 m <br /> (6 cm60 mm <br />0.06 m <br />) +
not overlapping +
papillose-hispid +, ascending +, puberulent +  and glabrous +
in triplets +  and paired +
0.27 cm2.7 mm <br />0.0027 m <br /> (0.42 cm4.2 mm <br />0.0042 m <br />) +
pubescent +  and glabrous +
6 +  and 60 +
unisexual +  and bisexual +
turgid +, ellipsoid +  and broadly obovoid +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.43 cm4.3 mm <br />0.0043 m <br />) +
1.7mm +  and 2.4mm +
1 +  and 3 +
fused +  and free +
2 +  and 3 +
dome--shaped +  and triangular +
Panicum oligosanthes +
Dichanthelium oligosanthes +
Dichanthelium sect. Oligosantha +
species +
membranous +
orange +  and purplish +
chartaceous-indurate +
more prominent +
7 (?) +  and 9 (?) +
plant +  and cespitose +
aquatic +  and terrestrial +
dioecious +, monoecious +  and synoecious +