Setaria leucopila
Setaria sphacelata
bristlegrass, plains bristlegrass, streambed bristlegrass, yellow bristlegrass, yellow foxtail
African bristle grass
20-100 cm.
50-150 cm, flattened;
nodes glabrous.
compressed, glabrous, margins villous distally;
ligules 1-2.5 mm, ciliate;
blades 8-25 cm long, 2-5 mm wide, flat or folded, scabrous on both surfaces.
glabrous;
blades 15-50 cm long, 4-10 mm wide, flat, rather lax.
6-15 cm, tightly spikelike, pale green;
rachises scabrous or villous;
bristles usually solitary, 4-15 mm, ascending.
5-25 cm long, 4-8 mm thick (excluding the bristles), densely spicate;
bristles 5 or more, 3-6 mm, usually orange to purple.
2.2-2.8(3) mm, elliptical.
2.5-3 mm, elliptic-oblong.
about 1/2 as long as the spikelets, 3-veined;
upper glumes from 3/4 as long as to equaling the florets, 5-veined;
lower lemmas equaling the upper lemmas, 5-veined;
lower paleas 1/2 - 3/4 as long as the upper paleas, lanceolate;
upper lemmas apiculate, finely and transversely rugose;
upper paleas similar.
about as long as the spikelets;
upper florets staminate;
upper glumes Vi-A as long as the spikelets;
lower lemmas equaling the upper lemmas;
lower paleas equaling the upper paleas, broad;
upper lemmas finely and transversely rugose;
upper paleas similar to the upper lemmas.
= 54, 68, 72.
= 36, 54.
Setaria leucopila
Setaria sphacelata
Setaria leucopila grows in the southwestern United States and northern Mexico. It is the most common of the perennial "Plains bristlegrasses."
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Setaria sphacelata is native to tropical Africa, but it has been found at a few scattered locations in the Flora region, often near a port. Clayton (1979) recognized five varieties of Setaria sphacelata. Those most likely to be introduced into the United States are Setaria sphacelata (Schumach.) Stapf & C.E. Hubb. var. sphacelata and S. sphacelata var. aurea (Hochst. ex A. Braun) Clayton, with var. aurea differing from var. sphacelata in having fibrous basal leaf sheaths and upper glumes that are often 3-veined.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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