Microstegium biaristatum (Steud.) Keng

This species is closely related to Microstegium fasciculatum, and the two are difficult to distinguish, at least in the herbarium. Microstegium ciliatum is a more slender species, forming loose mats rather than large, rambling colonies, usually with pale green rather than purplish inflorescences. The spikelets are narrower, with obviously longer, flexuous awns and an awned upper glume. Occasionally some spikelets in an inflorescence have tiny anthers (the basis of M. biforme).

The name "Ischnochloa monostachya L. Liu" (Fl. Reipubl. Popularis Sin. 10(2): 65. 1997) has been placed in synonymy under this species (in Fl. Yunnan. 9: 637. 2003), but was not validly published because no Latin description was provided.

Culm geniculate, slender, about 1 mm in diameter. Blade 7-8 cm long by; 4 mm wide, attenuate at both ends, sparingly hirsute on both surfaces; ligule chartaceous, about 1 mm long or more, hispid on the back; sheath margins ciliate. Inflorescence digitate, 3 to several racemes, racemes 5-6 cm long. Spikelets paired, monomorphic, both fertile, the upper pedicellate, the lower sessile, about 3.8 mm long; pedicel and rachis flattened, as long as the spikelets. Lower glume lanceolate, 2-keeled, shortly ciliate on keels; upper glume deltoid-lanceolate, 3-nerve,l-keeled, margins slightly inrolled, fimbriate, as long as the spikelet; lower floret reduced. Upper floret minute, about 0.5 mm long; lemma 1-nerved, with a sinus at the apex, topped by a long awn of about 25 mm long; palea oblong, with a sinus. Caryopsis oblong, about 1.5 mm long; embryo 1/2 the length of the caryopsis.

Rambling perennial, extensively rooting at the lower nodes; culms mostly 60-120 cm long. Leaf-blades broadly linear to narrowly lanceolate, thin, 5-15 cm long, 5-15 mm wide. Inflorescence composed of 3-20 subdigitate racemes, each 3-10 cm long; internodes linear, slightly widening upwards, shorter than the sessile spikelets, ciliate in two rows. Spikelets narrowly lanceolate, 2.5-4 mm long; lower glume with a V-shaped median groove, usually scaberulous on the back, bearded with white or purplish hairs about the callus, stiffly ciliate towards the apex; upper glume strongly keeled, the keel thrust between internode and pedicel, commonly with a short awn-point 0.5-2 mm long; lower floret absent, or represented by a little oblong scale; upper lemma minute, 0.5 mm long, cordate, with an awn 6-12 mm long; palea an almost square hyaline scale; anthers 3, each 1-1.5 mm long.

Perennial. Culms wiry, creeping, 1 m or more long, pubescent below inflorescence, nodes glabrous or pilose. Leaf sheaths pilose or glabrous, one margin ciliate; leaf blades linear-elliptic, 6–16 × 0.5–1.5 cm, adaxial surface thinly pilose with short tubercle-based hairs, abaxial surface softly pilose, apex acuminate into a setaceous point; ligule 1–2 mm. Racemes 3–15, flexuous, usually pale green, fastigiate, 6–10 cm; rachis internodes linear, slightly inflated upward, shorter than spikelet, margins ciliate. Sessile spikelet 3–4 mm; callus hairs 1–1.5 mm; lower glume narrowly lanceolate, back sharply grooved at lower midline, glabrous or scaberulous toward apex, 2-veined between keels, upper keels stiffly pectinate-ciliate, apex 2-toothed; upper glume sharply keeled, apex acuminate into a 0.3–3 mm hairlike awnlet; lower lemma absent or very small; upper lemma linear or lanceolate, occasionally broader, 0.5–1 mm, apex usually entire; awn 1–2 cm, flexuous with weakly developed column and fine hairlike apex. Anthers 3, 0.8–1.5 mm. Fl. and fr. Sep–Dec.

Himalaya (Nepal, Sikkim), India, Burma, Thailand, China, Taiwan.

Distributed in India, Burma, Indo-China to South China.

Distribution: Kashmir; India to Burma, China and the Philippines.

500-2000 m

Open woodlands, shady banks, pathsides, forming loose mats. Fujian, Guangdong, Guangxi, Guizhou, Hainan, Hunan, Jiangxi, Sichuan, Taiwan, Yunnan [Bhutan, India, Malaysia, Myanmar, Nepal, Sri Lanka, Thailand, Vietnam].

Pollinia ciliata Trin., Mem. Acad. St. Petersb. ser. 6. 2: 305. 1833.
Pollinia monantha var. formosana Hack., Bull. Herb. Boiss. 2(4): 527. 1904.
Pollinia formosana (Hack.) Hayata, Icon. Pl. Formos. 7: 76. 1918.
Microstegium formosanum (Hack.) A. Camus, Ann. Soc. L. Lyon n. s. 68: 201. 1921. Microstegium ciliatum var. integrum Ohwi, Act. Phytotax. Geobot. 11: 157. 1942.
Microstegium integrum Ohwi, Act. Phytotax. Geobot. 1l: 157. 1942.
Microstegium ciliatum subsp. integrum (Ohwi); Koyama, Grass. Jap. Neighb. Reg. 428. 1987

Pollinia ciliata Trinius, Mém. Acad. Imp. Sci. St.-Pétersbourg, Sér. 6, Sci. Math. 2: 305. 1833; Andropogon biaristatus Steudel; A. formosanus Rendle var. minor Rendle; Microstegium biaristatum (Steudel) Keng; M. biforme Keng; M. ciliatum var. formosanum (Hackel) Honda; M. ciliatum var. integrum Ohwi; M. formosanum (Hackel) A. Camus; Pollinia ciliata Trinius var. formosana (Hackel) Honda; P. formosana (Hackel) Hayata; P. monantha var. formosana Hackel.