Paul M. Peterson, Stephan L. Hatch and Alan S. Weakley
Plants annual. Culms 15-60 cm, ascending, glabrous. Sheaths shorter than the internodes, glabrous; ligules0.5-1 mm, ciliate; blades 4-12 cm long, 1.5-6 mm wide, flat, spreading, evenly distributed, adaxial surface sparsely ciliate-pustulate. Panicles 6-22 cm long, (1)5-13 cm wide, open, sometimes contracted; branchesterminating in a spikelet, lowest branches whorled, in verticles of 7-20; pedicels (2)3-6(8) mm, widely spreading, capillary. Spikelets 1.1-1.5 mm. Glumes thin, acute; lower glumes about 0.5 mm; upper glumes1.1-1.5 mm; lemmas 1.1-1.4 mm, acute; paleas 1-1.3 mm, hyaline. Fruits 0.6-0.9 mm, oblong, light brown; embryos 0.2-0.4 mm. 2n = unknown.
Sporobolus coahuilensis is primarily known from central Coahuila in Mexico. It has recently been found in Brewster and Hudspeth counties, Texas (Turner 2004).
Sporobolus coahuilensis appears closely related to the widespread species S. pyramidatus, and can be separated from the latter by its long capillary pedicels and usually wider panicles.