Leptochloa chinensis (L.) Nees
Family Poaceae, Tribe Chlorideae
Spikelets laterally compressed, 2–3.7(4.2) mm long, 0.75–1.3 mm wide, of 5–6 fertile florets, rachilla elongated between florets. Glumes hyaline to membranous, keeled, keels minutely barbed, lower glume usually shorter than upper glume. Floret dorsally compressed, elliptic, with narrow rachilla fragment ca. 0.3 mm long. Lemma (0.8)1.2–1.7(1.85) mm long, membranous to hyaline, keeled, palea twice keeled, both lemma and palea glabrous to hairy on surface, keels +/– hairy and minutely barbed. Caryopsis obovate, dorsally compressed, reddish-brown, 0.5–1.9 mm long, surface striate; embryo large; hilum small, round, indented.
Leptochloa panicea (Retz.) Ohwi ssp. brachiata (Steud.) N. Snow (non-FNW)
southeastern Africa, from Kenya to South Africa; Asia, from India and Sri Lanka to Southeast Asia, also China, Japan, and Korea; Australia, New Guinea
native to tropical Asia
wet, swampy or marshy sites; streams, ditches, grasslands, drains
Leptochloa chinensis is an annual or short-lived perennial grass, to 100 cm tall. This grass has become a serious weed in rice fields in Asian countries; it can grow profusely if waterlogged or flooded. The grains are much smaller than rice grains and can be removed during cleaning. Propagation is by grains or by stolons. Leptochloa chinensis has been used for fodder, and as a famine food in East Africa.
A–B, spikelets; A, with glumes; B, without glumes; C–G, florets; C,E,F, ventral view showing palea and rachilla; D,G, dorsal view showing lemma; H, caryopsis
A, spikelet; B, floret in side view; C, floret in ventral view; D, caryopsis in side view; E, caryopsis in dorsal view; drawing by Lynda E. Chandler