POACEAE 457at base, 5–35 cm tall, pubescent. Basal leaf sheaths tough, whit-ish, enclosing cleistogamous spikelets, finally becoming fi-brous; leaf blades usually involute, filiform, 2–12 cm, 1–3 mm wide, densely pubescent or the abaxial surface with longer white soft hairs, finely acuminate. Panicle gray, dense, spike-like, linear to ovate, 1.5–5 × 0.6–1 cm. Spikelets with 3 florets, 5.5–7 mm; glumes pubescent, 3–9-veined, lower glume 3–3.5 mm, upper glume 4–5 mm; lowest lemma 1.5–2 mm, densely villous; awns 2–4 mm, subequal, ciliate in lower 2/3 of their length; third lemma 0.5–3 mm, reduced to a small tuft of awns. Anthers 0.3–0.6 mm. Fl. and fr. Aug–Nov. 2n = 36. Dry hill slopes; 1000–1900 m. Anhui, Hebei, Liaoning, Nei Mon-gol, Ningxia, Qinghai, Shanxi, Xinjiang, Yunnan [India, Kazakhstan, Kyrgyzstan, Mongolia, Pakistan, E Russia; Africa, America, SW Asia]. This species is one of the most widespread in the genus and is the only one to develop cleistogamous spikelets within the basal leaf sheaths. Mature grains can often be found at the base of the plant. 2. Enneapogon persicus Boissier, Diagn. Pl. Orient., ser. 1, 5: 71. 1844. 波斯九顶草 bo si jiu ding cao Enneapogon schimperianus (A. Richard) Renvoize; Pap-pophorum aucheri Jaubert & Spach; P. persicum (Boissier) Steudel; P. schimperianum Hochstetter ex A. Richard; P. tur-comanicum Trautvetter. Perennial. Culms compactly tufted, wiry, erect or genicu-late, 15–45 cm tall, pubescent especially below nodes. Basal leaf sheaths tough, lacking cleistogamous spikelets, not becom-ing fibrous; leaf blades usually involute, rarely flat, often di-verging at a wide angle from the culm, 3–17 cm, 3–4 mm wide, pubescent, acuminate. Panicle olive-gray or tinged purplish, contracted to spikelike, narrowly oblong, 4–18 × 1–2 cm. Spikelets with 3 or 4 florets, 8–14 mm; glumes puberulous, (5–) 7–9-veined, lower glume 5–10 mm, upper glume 7–11 mm; lowest lemma 2–3.2 mm, shortly villous; awns 4.5–7 mm, un-equal with 4 shorter, ciliate in lower 2/3–3/4 of their length; third lemma sterile but well developed, 3–5 mm (including awns); fourth lemma vestigial or absent. Anthers 0.5–1.3 mm. Fl. May. 2n = 20. Dry, stony or sandy soils. Xinjiang [Afghanistan, NW India, Paki-stan, Tajikistan, Turkmenistan, Uzbekistan; NE Africa, SW Asia]. 22. Tribe ERAGROSTIDEAE 画眉草族 hua mei cao zu Chen Shouliang (陈守良), Wu Zhenlan (吴珍兰), Lu Shenglian (卢生莲), Sun Bixing (孙必兴 Sun Bi-sin); Sylvia M. Phillips, Paul M. Peterson Annual or perennial. Leaf blades linear to filiform; ligule a line of hairs, infrequently membranous. Inflorescence a panicle or composed of tough unilateral racemes of biseriate spikelets (bottlebrush in Harpachne); racemes digitate or scattered along an axis or rarely single, persistent or deciduous. Spikelets usually laterally compressed, with one floret or more usually several to many, the up-permost ± reduced, disarticulating below each floret or sometimes by other abscission modes; glumes mostly persistent, usually 1-veined, membranous and shorter than lowest lemma, rarely longer; floret callus sometimes bearded; lemmas membranous to leathery, 1–3-veined (7–11 in Aeluropus), glabrous or hairy, apex entire or 2–3-toothed occasionally with small subsidiary lobes be-tween teeth, mucronate or awned from apex or sinus; palea keels sometimes winged. Stamens 1–3. Fruit sometimes with free peri-carp. Leaf anatomy: Kranz PS type; microhairs usually short and stout. x = 10, less often 9, 12. About 80 genera and 1000 species; tropics and subtropics; 17 genera and 92 species (30 endemic, three introduced) in China. This tribe is characterized by unspecialized spikelets usually with several florets, 3-veined lemmas, and a rather cartilaginous texture, and also by a ciliate ligule, although there are exceptions to all these characters. This contrasts with the 5-veined lemmas and membranous ligule of most Poeae, which are often superficially similar, especially when the inflorescence is a panicle. Anatomically the two tribes are quite different. 1a. Spikelets with 1 floret. 2a. Ligule membranous; lemma 3-veined, awned; fruit a caryopsis ................................................................... 140. Muhlenbergia 2b. Ligule a line of hairs; lemma 1-veined, awnless; fruit with free pericarp. 3a. Inflorescence an open or spikelike panicle, exserted from uppermost leaf sheath ...................................... 138. Sporobolus 3b. Inflorescence a short dense head, subtended by an inflated leaf sheath with rudimentary blade ...................... 139. Crypsis 1b. Spikelets with 2 or more florets. 4a. Lemmas 7–11-veined ............................................................................................................................................ 124. Aeluropus 4b. Lemmas 3-veined (subsidiary veins in keel in Eleusine). 5a. Lemmas emarginate or 2-toothed at apex, or if entire marginal veins or flanks hairy. 6a. Cleistogamous spikelets concealed within the upper leaf sheaths ...................................................... 126. Cleistogenes 6b. Cleistogamous spikelets absent. 7a. Plants tall, reedlike; inflorescence a large plumose panicle ............................................................. 125. Neyraudia 7b. Plants smaller; inflorescence composed of racemes. 8a. Plants with long scaly rhizomes ....................................................................................................... 127. Orinus 8b. Plants lacking long scaly rhizomes. 9a. Inflorescence a single terminal raceme ................................................................................. 128. Tripogon 9b. Inflorescence of 2 to many racemes along a central axis. 10a. Racemes persistent; glumes shorter than lowermost lemma .................................... 129. LeptochloaPOACEAE 458 10b. Racemes deciduous; glumes as long as the spikelet ...................................................... 130. Dinebra 5b. Lemmas usually entire at apex, glabrous. 11a. Inflorescence a panicle .......................................................................................................................... 131. Eragrostis 11b. Inflorescence of one or more racemes. 12a. Inflorescence a single terminal raceme. 13a. Spikelets erect; lemmas disarticulating leaving the persistent paleas ........................... 132.