Dichanthelium laxiflorum

(Lam.) Gould
Common names: Soft-tufted panicgrass
Synonyms: Panicum ×alapense Panicum laxiflorum
Treatment appears in FNA Volume 25. Treatment on page 446.
Revision as of 03:04, 30 July 2020 by imported>Volume Importer
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Plants densely cespitose. Basal rosettes poorly differentiated; blades ovate to lanceolate. Culms 15-55 cm, slender, erect or radiating from a large tuft of predominantly basal leaves, lower internodes short, upper 3-5 internodes elongate; nodes bearded with soft, spreading or retrorse hairs; internodes glabrous; fall phase branching extensively from the basal nodes, forming a dense cushion that overwinters. Cauline leaves 2-4; sheaths usually longer than the internodes, pilose, hairs to 4 mm, retrorse or spreading; ligules 0.2-1 mm, at low magnification appearing to membranous and ciliate, at high magnification evidently of hairs that coherent at the base; blades 4-17 cm long, 4-12 mm wide, lanceolate, at least 3/4 as long as the basal blades, spreading to suberect, thin, soft, lax, yellowish-green, nearly glabrous or densely pilose on 1 or both surfaces, margins usually finely short-ciliate, at least on the basal 1/2, cilia not papillose-based. Primary panicles 4-12 cm long, 3-8 cm wide, well-exserted; secondary panicles more compact, usually not exserted above the crowded basal leaves; rachises and branches wiry, spreading or deflexed, often pilose. Spikelets 1.7-2.3 mm long, 1-1.2 mm wide, broadly ovate or oblong-obovoid, with papillose-based hairs, obtuse. Lower glumes 1/4 - 1/3 as long as the spikelets, broadly deltoid; upper glumes and lower lemmas subequal, usually fully covering the upper florets; upper florets 1.5-1.8 mm long, 1-1.2 mm wide, broadly ellipsoid or obovoid, minutely umbonate. 2n = 18.

Distribution

Md., Okla., Miss., Tex., La., W.Va., Pa., Mo., Ohio, Ala., D.C., Tenn., N.C., S.C., Va., Ark., Ill., Ga., Ind., Ky., Fla., R.I.

Discussion

Dichanthelium laxiflorum is a widespread, common species that grows in mesic deciduous woods, and occasionally in drier, more open woodlands. Its range extends south from the Flora region into Mexico. The density of the pubescence on the blade surfaces varies greatly.

The primary (spring) panicles are apparently chasmogamous; the secondary panicles are largely cleistogamous and are produced from late spring to winter.

Selected References

None.

Lower Taxa

None.

No values specified."usually distinctly longer and narrower" is not a number."decumbent" is not a number.

... more about "Dichanthelium laxiflorum"
rounded +  and attenuate +
anatomy +  and kranz +
Mary E. Barkworth +
(Lam.) Gould +
1 (?) +  and 3 (?) +
keeled +  and rounded +
pseudopetiolate +  and branching +
divergent +  and parallel +
coherent +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
membranous +
disarticulating +  and pseudopetiolate +
yellowish-green +
separable +
distinct +
4 cm40 mm <br />0.04 m <br /> (17 cm170 mm <br />0.17 m <br />) +
pilose +  and glabrous +
lanceolate +  and ovate +
deflexed;spreading +
spikelike +
0 cm0 mm <br />0 m <br /> (1 cm10 mm <br />0.01 m <br />) +
not developed +
terete +  and compressed +
not papillose-based +
sometimes longer +
Soft-tufted panicgrass +
branching +  and hollow +
decumbent +  and sprawling +
slender +
15 cm150 mm <br />0.15 m <br /> (55 cm550 mm <br />0.55 m <br />) +
Md. +, Okla. +, Miss. +, Tex. +, La. +, W.Va. +, Pa. +, Mo. +, Ohio +, Ala. +, D.C. +, Tenn. +, N.C. +, S.C. +, Va. +, Ark. +, Ill. +, Ga. +, Ind. +, Ky. +, Fla. +  and R.I. +
capillary +
germination +
pistillate +  and staminate +
sometimes longer +
compressed +  and terete +
shorter or longer +
subtending +
unequal +
membranous +
papillose-based +
spreading +  and retrorse +
uncinate +
0 cm0 mm <br />0 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
membranous +
Oval (?) +  and Round (?) +
bracteate +  and ebracteate +
coriaceous +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
membranous +
inconspicuous +
1/4 +  and 1/3 +
complex +  and simple +
concealed +  and prominent +
2 +  and 1 +
subterranean +
dry +  and fleshy +
4 cm40 mm <br />0.04 m <br /> (12 cm120 mm <br />0.12 m <br />) +
3 cm30 mm <br />0.03 m <br /> (8 cm80 mm <br />0.08 m <br />) +
deflexed +  and spreading +
usually longer +
in triplets +  and paired +
0.17 cm1.7 mm <br />0.0017 m <br /> (0.23 cm2.3 mm <br />0.0023 m <br />) +
pubescent +  and glabrous +
1 +  and 60 +
unisexual +  and bisexual +
obtuse +, oblong-obovoid +  and ovate +
0.11 cm1.1 mm <br />0.0011 m <br /> (0.23 cm2.3 mm <br />0.0023 m <br />) +
1mm +  and 1.2mm +
1 +  and 3 +
fused +  and free +
2 +  and 3 +
dome--shaped +  and triangular +
Panicum ×alapense +  and Panicum laxiflorum +
Dichanthelium laxiflorum +
Dichanthelium sect. Strigosa +
species +
membranous +
0.15 cm1.5 mm <br />0.0015 m <br /> (0.18 cm1.8 mm <br />0.0018 m <br />) +
umbonate +, obovoid +  and ellipsoid +
0.1 cm1 mm <br />0.001 m <br /> (0.12 cm1.2 mm <br />0.0012 m <br />) +
chartaceous-indurate +
plant +  and cespitose +
aquatic +  and terrestrial +
dioecious +, monoecious +  and synoecious +