Plants rhizomatous. Culms slender, 0.7-2.2 mm thick at the base. Uppermost sheath 0.7-2.5 mm wide. Panicles with 15-42 spikelets per cm2 when pressed. Fruits 1.3-1.6 mm.

Sporobolus compositus var. macer is known only from the south central United States.