Rhizomes short, covered with the persistent bases of the foliage leaves. Culms to 1.5+ m. Sheaths to 22 cm; ligules to 0.7 mm; blades to 85 cm long, 1.5-6.5 mm wide. Panicles 15-45 cm long, 8-40 cm wide, open; branches to 22 cm, ascending to spreading. Spikelets 6-7.4 mm. Glumes usually arcuate, acute to acuminate; lower glumes 2.7-4.1 mm; upper glumes 4.2-5.4 mm; callus hairs 1/3-1/2 as long as the lemmas; lemmas 5.5-7 mm, arcuate, pubescent, attenuate; paleas 5.4-6.2 mm, pubescent; anthers 2.8-3.2 mm. 2n = unknown.

Calamovilfa arcuata is known only from a few scattered locations in the south central United States. It grows along streams and rivers.