Plants usually cespitose, sometimes producing short rhizomes. Culms
30-210 cm. Sheaths usually glabrous, keeled; blades 9-45 cm long,
1.5-9 mm wide, flat, usually glabrous, occasionally pubescent. Peduncles
to 10 cm; rames 2-8 cm, with 6-13 spikelets, exserted. Sessile spikelets
6-11 mm; calluses about 0.5 mm, hairs to 2.5 mm, awns 2.5-17 mm;
Pedicels 3-7.5 mm, straight or curving out at maturity. Pedicellate
spikelets usually 1-6 mm, sterile, without lemmas, occasionally staminate
and with a lemma, unawned or awned, awns to 4 mm.
Schizachyrium scoparium var. scoparium grows in a variety of soils
and in open habitats. It was once a dominant component of the prairie grasslands
that extended through the central plains of North America and into Mexico, but
it has largely been replaced by fields of maize, wheat, sorghum, sunflowers,
and field mustard. It is the most variable of the varieties recognized within
S. scoparium, with morphological features that vary independently and
continuously across its range, coming together in distinctive combinations in
some regions. Some of these phases have been named as varieties, or even species,
but they have proven to be untenable taxonomic entities when plants from throughout
the range of the species are considered.