141. Lepturus R. Brown, Prodr. 207. 1810.
细穗草属 xi sui cao shu
Authors: Zhen-lan Wu & Sylvia M. Phillips
Perennial, rarely annual. Culms stoloniferous or decumbent. Leaf blades linear or linear-lanceolate; ligule membranous, margin ciliate. Inflorescence a single cylindrical bilateral raceme; spikelets alternate, sessile, borne edgeways and sunken in hollows on opposite sides of articulated rachis, falling with adjacent rachis internode; rachis terminating in a spikelet. Spikelets dorsally compressed, florets 1 or 2, disarticulating above glumes and between florets, rachilla extension with apical rudimentary floret present; lower glume minute or suppressed; upper glume leathery, appressed to rachis, exceeding and covering the sunken florets, closely 5–12-veined, apex acute to caudately awned; lemma much shorter than upper glume, rounded on back, cartilaginous to hyaline, 3-veined, apex obtuse to acute; palea membranous, usually equal to lemma. Caryopsis ellipsoid, pericarp free. x = 9. Leaf anatomy: Kranz PS type, with short stout microhairs.
Eight to fifteen species: shores of Indian and W Pacific Oceans; one species in China.
Lepturus has characteristic, sunken spikelets within a fragile rachis, unique in the tribe, but the leaf anatomy is typically chloridoid. Its precise affinities are uncertain, and it is sometimes placed in its own tribe, Leptureae.