Culms 30-80 cm, erect, or decumbent and rooting at the nodes. Blades 6-12 cm long, 5-10 mm wide, usually folded, apices obtuse. Panicles with (6)8-15 branches; branches 4-10 cm, straight, somewhat stiff. Spikelets 1.5-2.1 mm; florets 2. Lower glumes 1.1-1.3 mm, linear-lanceolate, acute; upper glumes 1.3-1.5 mm, oblanceolate, apices truncate or bilobed, mucronate, mucros to 0.4 mm; calluses with a few short hairs; lowest lemmas 1.7-2 mm, lanceolate to ovate, not strongly keeled, midveins glabrous, lateral veins with widely spreading, white, 1-2 mm hairs, apices acute to mucronate; second lemmas 1.1-1.2 mm, broadly cuneate, apices truncate. Caryopses about 1 mm. 2n = 40.
Tex., N.Y., Ga., S.C., N.J., Fla.
Eustachys retusa is native to South America, but it is now established along roadsides, sandy fields, and waste areas in the southeastern United States.