Plants annual. Culms (30)60-250 cm, mostly erect, compressed, sometimes branching from the lower nodes; internodes hollow. Sheaths glabrous, smooth or minutely scabrous; ligules 1.5-3 mm, membranous, truncate, erose, sometimes appearing ciliate because of the hairs at the base of the blades; blades 10-75 cm long, 4-7 mm wide, sometimes with stiff hairs behind the ligules, both surfaces scabridulous elsewhere. Panicles 30-76 cm, with 25-75 racemose branches; branches mostly 1-5(9) cm, steeply ascending to erect, stiff, lower branches sometimes included in the upper leaf sheaths. Spikelets 2.8-3.4 mm, imbricate, with 3-4 florets. Glumes lanceolate, lower glumes 0.7-0.8 mm, acute to narrowly obtuse; upper glumes 0.9-1.3 mm, obtuse; lemmas 1-2 mm, broadly lanceolate, membranous, veins sericeous basally, apices obtuse to acute or apiculate; paleas sericeous along the veins; anthers 3, 0.2-0.4 mm. Caryopses 0.5-1 mm long, 0.4-0.5 mm wide, elliptic to obovate, nearly round in cross section. 2n = 40.

Leptochloa nealleyi is native to coastal Louisiana, Texas, and Mexico; it also grows, but rarely, in Cuba. The species is not established in Arizona, but it was collected once from a farm in the Wellton area (NCU 303513). It is not clear whether the plants were being cultivated or growing as weeds.

The numerous, short, stiffly ascending or erect panicle branches make Leptochloa nealleyi easy to identify.