221. Hackelochloa Kuntze, Revis. Gen. Pl. 2: 776. 1891.
球穗草属 qiu sui cao shu
Authors: Bi-xing Sun & Sylvia M. Phillips
Annual. Leaf blades flat, linear or linear-lanceolate; ligule a short ciliate membrane. Inflorescence of single axillary racemes aggregated into a spathate compound panicle, peduncle enclosed within spatheole; racemes flattened, dorsiventral, bearing paired spikelets, fragile, obliquely articulated; rachis internodes stoutly oblong, adnate to adjacent pedicel, together forming a cavity, base obliquely truncate with central peg. Sessile spikelet much broader than internode; lower glume brittle, hemispherical, rugose, pitted to honeycombed, wingless, narrowed into a stipelike base; upper glume shorter and narrower, sunk into cavity of rachis; lower floret barren, without a palea; upper floret with entire awnless lemma. Pedicelled spikelet readily disarticulating, narrowly ovate, herbaceous, smooth, narrowly winged; pedicel oblong, adnate to adjacent rachis internode, junction with internode marked by a line. x = 7.
Two species: one pantropical, the other confined to Asia; two species in China.
This genus is readily recognizable by its unique, globose, reticulately wrinkled sessile spikelets. The caryopsis is unusual, as the embryo extends along its whole length. It is placed in Mnesithea by some authors, but differs from that genus also by its annual habit and different basic chromosome number.