28. Tribe ANDROPOGONEAE

POACEAE 609composed of 3–5(–)8 racemes, subdigitate; racemes 3–8 cm,tinged purplish; rachis internodes and pedicels ciliate with longsilky hairs. Sessile spikelet 3–4.5 mm; lower glume narrowlyelliptic, cartilaginous, back concave, 5–7-veined, glossy, sparselyhirtellous to silky-pilose below middle, a circular pit abovehairs, 2-keeled, margins keeled and scabrid near apex; awn ofupper lemma 1–2 cm. Pedicelled spikelet male or barren, purplish,subequal to sessile spikelet, glabrous. Fl. and fr. Jul–Oct.2n = 40, 60.Grassy hills, disturbed ground; 1200–1500 m. Guangdong, Sichuan,Yunnan [India, Indonesia, Malaysia, Nepal, Pakistan, Thailand,Vietnam; introduced in Australia and United States].The type of Bothriochloa nana is a stunted specimen of B. pertusawith the spikelets infected by a smut fungus.204. SEHIMA Forsskål, Fl. Aegypt.-Arab. 178. 1775.沟 颖 草 属 gou ying cao shuSun Bixing ( 孙 必 兴 Sun Bi-sin); Sylvia M. PhillipsPerennial or annual. Culms tufted, simple or sparingly branched. Leaf blades narrowly linear; ligule a line of hairs. Inflorescencea single terminal raceme, spikelets paired, dissimilar; rachis internodes and pedicels subinflated, stoutly linear to subclavate,densely white-ciliate along margins. Sessile spikelet bisexual, narrow, compressed between internode and pedicel; callus rounded, insertedinto shallowly hollowed internode apex; lower glume leathery, back concave or longitudinally grooved, strongly veined oneither side of groove but midvein absent, 2-keeled, keels lateral or becoming dorsal toward base, barely winged, apex elongate, scarious,2-toothed; upper glume boat-shaped, finely awned; lower floret staminate, well developed with palea; upper lemma 2-lobed,awned from sinus; awn geniculate, column glabrous or ciliolate. Pedicelled spikelet large, conspicuous, usually staminate, lanceolate,strongly dorsally compressed, distinctly veined, midvein present, awnless. x = 10 and 20.Five species: E Africa through India to SE Asia and Australia; one species in China.1. Sehima nervosum (Rottler) Stapf in Prain, Fl. Trop. Africa9: 36. 1917.沟 颖 草 gou ying caoAndropogon nervosus Rottler, Ges. Naturf. Freunde BerlinNeue Schriften 4: 218. 1803 [“nervosum”]; Ischaemum laxumR. Brown; I. nervosum (Rottler) Thwaites.Perennial. Culms erect, wiry, 30–100 cm tall, nodesbearded or glabrous. Leaf sheaths glabrous or hispid withtubercle-based hairs; leaf blades linear, flat, tough, pale green,10–45 × 0.2–0.7 cm, scabrid, tapering to a filiform apex; ligule2–3 mm. Raceme 3–12(–18) cm, straight or gently curved;rachis internodes and pedicels stoutly linear, 3.5–5 mm. Sessilespikelet yellowish green, 7–9 mm; lower glume narrowlyoblong, deeply grooved between keels in lower part, with 6prominent laterally placed intercarinal veins, inner veinsanastomosing toward apex, apex scarious, 1/4–1/3 glumelength, shortly 2-toothed; upper glume with straight, 7–13 mmawn; awn of upper lemma stout, 1.7–3.5 cm, column brown,ciliolate along spiral, limb pallid. Pedicelled spikelet usuallyflushed purple, 7–10 mm, lower glume conspicuously 7-veined,margins ciliate. Fl. and fr. Jul–Oct.Dry grasslands; at low elevations. Hainan, Yunnan [India, Indonesia,Laos, Myanmar, New Guinea, Pakistan, Philippines, Sri Lanka,Thailand, Vietnam; E Africa, SW Asia, Australia].205. ISCHAEMUM Linnaeus, Sp. Pl. 2: 1049. 1753.鸭 嘴 草 属 ya zui cao shuSun Bixing ( 孙 必 兴 Sun Bi-sin); Sylvia M. PhillipsPerennial, or sometimes annual. Culms often decumbent and much branched. Leaf blades linear to lanceolate, narrowed toligule, sometimes pseudopetiolate; ligule membranous; sheath auricles often present. Inflorescence of paired racemes, or occasionallysubdigitate, terminal and axillary, exserted or sometimes supported by a spatheole; racemes 1-sided, when paired oftenlocked back to back and appearing as a single cylindrical raceme, spikelets of a pair similar or not; rachis internodes and pedicelsstoutly linear to thickly clavate, U-shaped or triquetrous in cross section. Sessile spikelet dorsally compressed; callus truncate or obtuse,inserted into hollowed internode apex; lower glume papery to leathery, shallowly convex or almost flat, 2-keeled or rounded onflanks, sometimes winged, often rugose; upper glume boat-shaped, awnless or with straight awn from apex; lower floret male, welldeveloped with palea; upper lemma usually deeply 2-lobed, awned from sinus, rarely awnless; awn geniculate, glabrous. Pedicelledspikelet as large as sessile or much smaller, upper lemma sometimes geniculately awned.About 70 species: throughout the tropics but mainly in Asia, especially India; 12 species (one endemic) in China.1a. Margins of lower glume of sessile spikelet broadly rounded in lower part, narrowly inflexed and keeled above, notcoarsely rugose or knobbly.2a. Spikelets of a pair without obvious awns, or only sessile spikelet awned.3a. Inflorescence base enclosed in uppermost sheath; plant strongly rhizomatous ................................................ 1. I. muticum3b. Inflorescence long exserted from uppermost sheath; plant loosely tufted.