152. Perotis Aiton, Hort. Kew. 1: 85. 1789.
茅根属 mao gen shu
Authors: Shou-liang Chen & Sylvia M. Phillips
Diplachyrium Nees.
Annuals or sometimes perennials. Leaf blades short, broad, base slightly cordate, margins often pectinate-ciliate; ligule a membranous rim. Inflorescence a cylindrical raceme of long-awned, solitary spikelets borne directly on main axis; rachis clothed in short pegs after spikelets have fallen. Spikelets linear-elliptic, terete or slightly laterally compressed, with 1 floret, falling entire, subsessile or borne on a pedicel-like callus which falls with spikelet; glumes subequal, as long as spikelet and enclosing floret, papery, 1-veined, rounded, scabrous, apex with a long slender awn far exceeding glume body, lower glume tightly embraced by upper glume, its awn usually longer than upper glume awn; lemma lanceolate, shorter than glumes, hyaline, 1-veined, glabrous, acute; palea hyaline, slightly shorter than lemma, flattened. Caryopsis terete or flattened, apex acute.
Thirteen species: Old World tropics; three species in China.
This is an easily recognizable genus on account of the delicate, elongate, violet-tinged, "bottlebrush" inflorescence of small, long-awned spikelets, which fall entire from the central axis.
