Plants perennial; cespitose from a hard, knotty base, without rhizomes.
Culms 5-100 cm, erect, sometimes branching, mostly glabrous but
sometimes scabrous beneath the panicle; nodes glabrous. Leaves green; sheaths
glabrous or pubescent, margins ciliate; ligules 0.6-1.2 mm, membranous,
ciliate; blades 2-45 cm long, 2.5-7 mm wide, flat, glabrous or
pubescent, margins ciliate or glabrous basally. Panicles 2-13.8
cm long, 4-11 mm wide, erect, green or dark purple; rachises terete,
scabrous. Fascicles
11-24 per cm, disarticulating at maturity; fascicle axes 0.2-1.1
mm, with 1-12 spikelets; outer bristles 10-62, 0.1-1.8 mm, not
exceeding the spikelets;
inner bristles 6-32, 1.2-5 mm, ciliate, fused for 1/3-1/2 their
length; flattened, grooved; primary bristles 2.9-6.5 mm, ciliate,
not noticeably longer than the other bristles. Spikelets 3.1-5.3
mm, sessile, glabrous;
lower glumes 1-2.5 mm, 0-1-veined; upper glumes 1.5-3.4 mm,
(0)1-3-veined, about 1/2 as long as the spikelet; lower florets staminate
or sterile;
upper florets not disarticulating at maturity; lower lemmas 2.7-5.3
mm, 3-7-veined; lower paleas absent or 2.5-4.5 mm; anthers absent
or 0.9-3 mm; upper lemmas 2.8-5 mm, 3-5-veined; anthers 3,
2-3.2 mm. Caryopses 1.2-1.8 mm long, 0.4-1 mm wide. 2n =
34, 36, 37, 54, 72.
Pennisetum setigerum is grown as a forage grass in the southern United
States, but is not known to be established in the Flora region. It is sometimes
included in Cenchrus, based solely on the fusion
of its bristles.