Plants cespitose. Basal rosettes well-differentiated;
blades 2-4 cm, pubescent, reddish. Culms 18-75 cm, usually more
than 1 mm thick, occasionally delicate, erect or ascending; nodes glabrous;
internodes glabrous; fall phase with decumbent culms, branches
arising from the lower and midculm nodes, rebranching 2-3 times, with small
blades and secondary panicles compared to those on the culms, secondary panicles
with 8-10 spikelets, partially included at maturity. Cauline leaves 3-5;
sheaths shorter than the internodes, lower sheaths pubescent, upper sheaths
glabrous, margins of all sheaths sparsely ciliate; ligules about 0.5
mm, of hairs; blades 5-11 cm long, 5-13 mm wide, thin, spreading to erect,
usually glabrous, rarely pubescent abaxially, always glabrous adaxially, bases
truncate to cordate, ciliate on the margins, blades of the flag leaves erect
or ascending. Primary panicles 5-11 cm long, 3-8 cm wide, ovoid, long-exserted,
with 40-220 spikelets. Spikelets 2-2.2 mm long, 0.8-1.3 mm wide, ellipsoid,
usually reddish, shortly pubescent, subacute. Lower glumes 0.5-1 mm,
triangular-ovate; lower florets sterile; upper florets slightly
exceeding the upper glumes and lower lemmas, subacute. 2n = 18.
Dichanthelium boreale grows inopen woodlands and thickets, wet meadows,
and fields within the Flora region. The primary panicles are mostly open-pollinated
and are produced in May and June; the secondary panicles are predominantly cleistogamous
and are produced from mid-June into October.
Dichanthelium boreale occasionally hybridizes with D.
acuminatum and D. xanthophysum, producing a sterile triploid sometimes called Panicum calliphyllum
Ashe.
Culms 2-7 dm, usually erect or nearly so, in tufts of 2-10, glabrous, or villosulous at the nodes; lowest sheaths usually papillose-pilose, the upper merely ciliate, often longer than the internodes; ligule obsolete, or a band of short hairs not over 1 mm; blades erect or strongly ascending, firm, rounded at the ciliate base, tapering from below the middle, glabrous or rarely hairy beneath, mostly 5-15 cm נ(4-)6-14(-16) mm, the upper scarcely reduced; primary panicle long-exsert, relatively few-fld, 5-10 cm, the lower branches ascending; spikelets long-pedicellate, minutely hairy, ellipsoid, 1.9-2.3 mm; first glume a fourth to two-fifths as long; second glume and sterile lemma usually purplish, subequal, equaling or barely shorter than the fr; autumnal phase similar, with a few lax branches at the upper nodes bearing somewhat smaller lvs and shorter, few-fld panicles; 2n=18. Open woods, fields, and shores; Que. and Nf. to Minn., s. to N.J. and n. Ind. (P. bicknellii; P. bushii; P. calliphyllum; Dichanthelium b.) It is possible that some of the plants usually referred here are hybrids between broad-lvd and narrow-lvd spp.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.