12. Isachne myosotis Nees, Hooker’s J. Bot. Kew Gard. Misc. 2: 98. 1850.
荏弱柳叶箬 ren ruo liu ye ruo
Isachne micrantha Merrill; I. myosotis var. micrantha (Merrill) Jansen; I. myosotis var. minor Honda; I. nipponensis var. minor (Honda) Nemoto.
Small mat-forming annual. Culms very slender, prostrate, branching and rooting at nodes, flowering branches up to 10 cm tall. Leaf sheaths thinly to densely hispid with spreading hairs, or hairs confined to margins; leaf blades lanceolate-ovate, 1–2(–3) × 0.2–0.5 cm, both surfaces hispid, densely or sometimes inconspicuously appressed-hairy, base rounded, apex acute; ligule ca. 0.7 mm. Panicle ovate or contracted, 1.5–5 cm, eglandular, spikelets usually 15–30 (fewer in depauperate specimens); branches spiculate to base, with short stiff branchlets and pedicels, smooth. Spikelets subglobose, 1–1.4 mm, tinged purplish; florets similar; glumes equal to spikelet, separated by a short internode, ovate-oblong, 5(–7)-veined, hispid usually above middle, occasionally hispid almost to base or almost glabrous, apex obtuse; lemmas strongly convex, leathery, puberulous to densely pubescent. Fl. and fr. May–Oct. 2n = 20.
Wet ground, shallow water in ditches. Fujian, Taiwan [Indonesia, New Guinea, Philippines].
This small species is recognizable on account of its delicate, mat-forming habit, small, broad leaf blades, smooth panicle branches, and tiny spikelets. It is barely separable from Isachne pauciflora.