Annual, 20-135 cm tall; calms slender, +/- erect, geniculate and rooting at lower nodes. Sheaths shorter than the internodes, keeled, glabrous to pubescent; blades 3-30 cm long, 6-20 mm wide, glabrous to pubescent, the margins scabrid. Panicles of 6-35 slender, solitary, or fasciculate racemes 3-8 cm long; rachis narrowly winged, with scattered long trichomes; spikelets paired on slender pedicels, piano-convex, ca 1.5 mm long, short-spreading pubescent; first glume lacking; second glume and sterile lemma covering fruit. Fruits ca 1.5 mm long, pale green, smooth. Shattuck 465. Collected by Shattuck at the end of Miller Trail, probably in the Front Lighthouse Clearing; the species may no longer occur on the island. Flowering and fruiting chiefly at the end of the rainy season. Guatemala to Brazil. In Panama, known from tropical moist forest in the Canal Zone, Bocas del Toro, Chiriqui, and Panama and from tropical dry forest in Panama (Taboga Island).