Plants cespitose. Basal rosettes poorly differentiated; blades similar
in shape to the lower cauline blades, narrow, ascending. Culms 10-50
cm, very slender, erect to drooping, lower 3-8 internodes telescoped together,
less than 2 cm, upper 2 internodes elongated; nodes bearded; internodes
pubescent to almost glabrous; fall phase developing a dense mass of erect
blades and foreshortened branches arising from the basal nodes, terminating
in small, narrow secondary panicles that are enclosed within the sheaths, with
6-15 spikelets. Cauline leaves 2-4; sheaths longer than the internodes,
glabrous or pilose with dense, fine, papillose-based hairs; ligules about
0.5 mm; blades 5-20 cm long, 2-5 mm wide, stiffly ascending to erect,
green to grayish-green, glabrous or densely pilose, apices long-tapering, lower
blades shorter than the upper 2 or 3 blades. Primary panicles 4-10 cm
long, 2-6 cm wide, long-exserted, with 12-70 spikelets; branches and
pedicels spreading. Spikelets 2-3.2 mm long, 0.8-1.4 mm wide,
ellipsoid, not turgid, sparsely pubescent. Lower glumes 0.6-1.1 mm, ovate-triangular;
upper glumes and lower lemmas exceeding the upper florets by about
0.2 mm before flowering, subequal in fruit, slightly pointed at maturity, upper
florets 1.7-2.3 mm, ovoid-ellipsoid, minutely umbonate. 2n = 18.
Dichanthelium linearifolium grows in dry, open woodlands, rock
outcroppings, and sandy areas. It is restricted to the Flora region.
The primary panicles are briefly open-pollinated, produced from May
to early June; the secondary panicles are cleistogamous, produced from
late June through July (rarely in fall). Plants in the northern United
States and Canada tend to be shorter and more spreading, subglabrous,
and to have spikelets 2-2.6 mm long; they have been called Panicum
werneri Scribn., but do not merit taxonomic recognition.
In the southwestern part of its range, especially in the Ozarks, most
plants of D. linearifolium are tall, erect, densely pilose, with
very elongated blades and spikelets often 2.6-3 mm long; they may hybridize
with D.
perlongum.
Vegetatively much like no. 17 [Panicum depauperatum Muhl.], avg somewhat taller and eventually more branched; primary panicle more numerously fld, usually much surpassing the lvs, at maturity open, the longest pedicels 8-18 mm; spikelets ellipsoid, 1.7-3.1 mm, glabrous to pilose; second glume and sterile lemma blunt, about equaling the fr; 2n=18. Dry or stony soil, open woods, and banks; N.S. and Que. to Minn., s. to Ga. and Tex. (P. werneri; Dichanthelium l.) Occasional plants intermediate toward no. 17, called P. perlongum Nash, may be of hybrid origin.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.