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.
Plants perennial, with both fertile and sterile shoots; cespitose,
not rhizomatous. Culms (30)50-110 cm, erect, glabrous or pubescent. Leaves 2-3
per culm; sheaths scabridulous or pilose; ligules 1.5-3 mm,
truncate, erose to lacerate; blades (8.5)15-20+ cm long, (3)7-12 mm wide,
flat, ascending, lax at maturity, often scabridulous. Panicles 10-30
cm long, (1)2-9 cm wide, open, nodding, green or tan, occasionally purple-tinged; branches 2-12+
cm, most, except sometimes the uppermost, spikelet-bearing only towards
the apices, with the basal (1/5)1/3-1/2 bare, filiform, flexuous, at least
the lowermost 1-3 whorls spreading or drooping. Spikelets 6-12 mm,
subsessile to pedicellate, pedicels to 2 cm, usually with 2-3 functional
florets below 1-2 reduced florets; rachilla internodes and hairs 1-2.5
mm; disarticulation above the glumes and between the florets. Glumes unequal; lower
glumes 0.75-2(3) mm, subulate; upper glumes 3.5-5 mm long, shorter
than the lowest florets, 2-3 times as wide as the lower glumes, widest
at or above the middle, ovate or obovate, rounded to the acuminate apices; callus
hairs to 1 mm; lemmas 5-6 mm, broadly lanceolate, glabrous,
bifid, teeth to 1.3 mm, awned, awns (7)9-14 mm, arising from above midlength
to just below the teeth, conspicuous, arcuate to flexuous; paleas shorter
than the lemmas; anthers about 1 mm. Caryopses about 2.5-3.2
mm, densely to sparsely pubescent. 2n = 42.
Trisetum cernuum grows in moist woods, stream banks, lake and pond
shores, and floodplains of the western Flora region. The hairiness
of the leaf sheaths varies, often within a plant.