1. Isachne hainanensis P. C. Keng, Acta Phytotax. Sin. 10: 23. 1965.
海南柳叶箬 hai nan liu ye ruo
Annual. Culms slender, creeping, branching and rooting at lower nodes, 8–15 cm tall. Leaf sheaths shorter than internodes, papillose-hispid, outer margin ciliate; leaf blades ovate-elliptic, thin, 0.8–1.5 × 0.3–0.6 cm, subglabrous or abaxial surface papillose-hispid, base rounded, margins not thickened, ciliate, apex acute; ligule almost absent. Panicle ovate in outline, 2–3.5 cm, eglandular, moderately branched; branches and pedicels slender, pedicels mostly longer than spikelets. Spikelets 1.7–1.8 mm, greenish or purplish green; florets clearly dissimilar; lower floret male, upper floret raised on distinct internode, bisexual; glumes subequaling or shorter than spikelet, elliptic-lanceolate, 5–7-veined, glabrous, apex obtuse; lower lemma herbaceous, elliptic-oblong, dorsally flattened, smooth, glabrous; anthers 1.3–1.5 mm; upper lemma crustaceous, strongly plano-convex, 1/2 length of lower floret, densely pubescent. Fl. and fr. Oct–Dec.
* Valleys, moist places; 300–500 m. Guangdong, Hainan.
This species is very close to Isachne pulchella, but the whole plant is eglandular and has exceptionally small leaf blades and a small upper floret raised on a conspicuous internode. The anthers are also longer than in I. pulchella.