Small annual, to 50 cm tall, usually growing as isolated individuals, usually unbranched, the base sometimes decumbent; culms glabrous, with nodes bearded. Sheaths glabrous or ciliate on margin, shorter than internodes; blades 1.5-10 cm long, to 3 mm wide, conspicuously pubescent on upper and lower surfaces, the trichome bases enlarged. Racemes usually 5 or 6 clustered near apex, 3-6 cm long, held well above leaves; rachis and sterile pedicel prominently long-villous; spikelets in pairs, one sessile and perfect, the other pedicellate and sterile; sessile spikelet awned, 3.5-4 mm long, the glume with a prominent small, round, deep pit above the middle; awns brown, generally twice-geniculate, to ca 2 cm long; pedicellate spikelet awnless, about as long as sessile one. Fruits not seen. Croat 9206. Occasional, in open areas in the Laboratory Clearing during the dry season. Bothriochloa bladhii (Retz.) S. T. Blake, native to India and Africa, has a pit in the glume similar to that in B. pertusa, but it has not been collected on the island.