Plants annual; sometimes stoloniferous. Culms 10-100 cm, erect to ascending, branching above the base. Leaves mostly cauline; ligules of hairs; blades linear. Inflorescences numerous, terminal and axillary, subdigitate or racemose panicles of spikelike branches, spikelets borne singly in 2 rows on the abaxial sides of the branches; disarticulation at the base of the spikelets. Spikelets dorsally compressed, with 2 florets, upper floret appressed to the branch axes. Glumes mostly absent, upper glume sometimes present on the terminal spikelet of a branch; lower florets sterile; upper florets bisexual; lower lemmas subequal to the upper lemmas; upper lemmas membranous to coriaceous, margins narrow; upper paleas similar in texture to the lemmas, their bases enclosed by the lemmas; anthers 1 or 2. x = unknown. Named for J.A.H. Reimarus (1729-1814), a German botanist and professor of natural history and physics at Hamburg, and the Greek chloa, grass.