Description from Flora of China
Diandranthus L. Liu; Imperata subg. Triarrhena Maximowicz; Rubimons B. S. Sun; Triarrhena (Maximowicz) Nakai.
Perennial, tufted or rhizomatous. Culms slender to robust, erect, solid. Leaves basal or cauline; leaf blades large, linear, flat, broad or narrow; ligule membranous. Inflorescence a panicle, often large and plumose, of racemes arranged on a long or short axis; raceme axis tough, internodes slender, spikelets paired, both spikelets pedicelled, pedicels slender, flattened, slightly clavate. Spikelets similar, lanceolate, dorsally compressed; callus bearded with hairs shorter than, as long as, or longer than the spikelet; glumes papery or membranous; lower floret usually represented by a hyaline sterile lemma; upper floret bisexual, lemma hyaline, awned or awnless. Stamens 2–3. Caryopsis oblong or ellipsoid.
This genus is readily recognized by its paniculate inflorescence of racemes, which have a tough rachis, and also by its paired spikelets, both of which are pedicelled.
Fourteen species, mostly in SE Asia and the Pacific Islands, extending to tropical Africa; seven species (two endemic) in China.
(Authors: Chen Shouliang (陈守良); Stephen A. Renvoize)