Plants perennial, sometimes with both fertile and sterile shoots;
cespitose, not rhizomatous. Culms 40-120 cm, erect, usually smooth. Leaves 3-4
per culm; sheaths crisped-pubescent to shaggy-pilose, scabrous or
smooth; ligules (1.5)3-6 mm, rounded to truncate; blades 10-30
cm long, (3)7-10 mm wide, flat, erect, lax, margins (and occasionally surfaces)
sometimes with scattered 1-3 mm hairs. Panicles 10-25 cm long, (0.75)1-3(4)
cm wide, narrow, erect or nodding at the apices, green or tan, occasionally
purple-tinged; branches 1-5.5 cm, ascending to somewhat divergent,
most spikelet-bearing for their full length, sometimes the lowermost branches
naked below. Spikelets 7-9 mm, pedicellate, with 2-4 florets; rachilla
internodes 1.5-3 mm; rachilla hairs 0.7-1 mm; disarticulation above
the glumes and between the florets. Glumes unequal to subequal; lower
glumes 3-5 mm, narrow, lanceolate to subulate, acute or long-tapered; upper
glumes (3.5)5-7(9) mm long, shorter than the lowest florets, at least
twice as wide as the lower glumes, broadly lanceolate to obovate, widest
at or below the middle, tapering to the apices, acute; callus hairs about
0.5 mm; lemmas 5-7 mm, glabrous, apices bifid, teeth to 2.5(3.2)
mm, setaceous, awned, awns 7-14 mm, arising mostly at the upper 1/3 of
the lemmas, geniculate; paleas as long as or slightly longer than
the lemmas; anthers 1-3 mm. Caryopses usually to 3 mm, glabrous
or finely hairy distally. 2n = 28, 42.
Trisetum canescens grows at or near stream banks, and in forest
margins or interiors, in moist to dry areas in the western Flora region.
It is especially abundant in ponderosa pine stands and spruce-fir forests.
The vestiture of different parts varies throughout the range of the species.
Plants from California with conspicuously interrupted panicles have been
called Trisetum cernuum var. projectum (Louis-Marie) Beetle.