Plants perennial; cespitose, without rhizomes or stolons. Culms
20-60 cm, stiffly erect, glabrous. Sheaths mostly glabrous, a few long
hairs present near the ligules; ligules 0.2-0.5 mm, of hairs; blades
6-16 cm long, 1-2 mm wide, involute when dry, glabrous, bases usually with papillose-based
hairs on the margins. Panicles 5-10(14) cm, with 15-70 branches; branches
5-9 mm, deciduous, scabrous, with 1 spikelet (lower branches occasionally with
2 spikelets), axes extending 3-4 mm beyond the terminal spikelets, apices entire;
disarticulation at the base of the branches. Spikelets appressed,
with 1 bisexual and 0-1 rudimentary florets. Glumes acute to slightly
cleft and minutely apiculate, midveins usually scabrous; lower glumes
2.5-4 mm; upper glumes 6.2-8 mm, mostly smooth, midveins usually scabrous;
lowest lemmas 6-7.5 mm, acute or minutely cleft, glabrous, unawned, sometimes
mucronate; lowest paleas unawned, glabrous; anthers 2.5-3 mm, bright
yellow; second florets absent or reduced to 1 or 3 short awns, glabrous.
Caryopses about 3 mm. 2n = 20.
Bouteloua uniflora grows primarily in fertile, rocky, limestone
soils of Texas and adjacent Coahuila, Mexico at 300-1000 m. A disjunct
collection has been reported from Zion National Park, Utah. Plants in
region belong to Bouteloua uniflora Vasey var. uniflora,
which differs from B. uniflora var. coahuilensis Gould
& Kapadia in having taller (40-60 cm, not 20-40 cm) leafy, rather than
scapose, culms, longer leaf blades (12-16 cm versus 6-12 cm), and 50-70,
rather than 15-40, panicle branches.