Isachne

This is a distinctive species with remarkably short leaf sheaths, exposing long lengths of internode, and a small, stiff panicle of horizontally tiered branches.

Perennial. Culms stiffly erect, 35–45 cm tall, unbranched, nodes widely spaced, glabrous. Leaf sheaths very short, much shorter than internodes and shorter than blade, slightly inflated, glabrous or setose; leaf blades lanceolate-ovate, thick, tough, 1–2.5 × 0.3–0.7 cm, veins many, riblike, abaxial surface minutely papillose, adaxial surface scabrid or hispidulous on veins, margins pectinate-setose, apex acuminate; ligule absent. Panicle broadly pyramidal, 1.5–4 cm, glandular; branches stiff, horizontally spreading, close-set, smooth; pedicels stout, shorter than or equaling spikelets. Spikelets globose, 1.2–1.3 mm, brownish green; florets similar; glumes shorter than florets, thickly membranous with broad scarious margins, lower glume 3-veined, upper glume 5-veined, densely hispid with thick hairs, apex rounded; lemmas strongly plano-convex, leathery, back minutely white-granular, margins scurfy-pubescent, lower lemma very slightly longer and narrower.

Shallow soil over rocks, swampy grasslands, lake and stream margins, sometimes in shallow water. Hong Kong [India (Nicobar Islands), Indonesia, Malaysia, Myanmar, New Guinea, Thailand, Vietnam; Australia].

Perennials, Terrestrial, not aquatic, Stems nodes swollen or brittle, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems terete, round in cross section, or polygonal, Stems branching above base or distally at nodes, Stem nodes bearded or hairy, Stem internodes hollow, Stems with inflorescence less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathi ng at base, Leaf sheath mostly open, or loose, Leaf sheath hairy, hispid or prickly, Leaf sheath and blade differentiated, Leaf blades disarticulating from sheath, deciduous at ligule, Leaf blades lanceolate, Leaf blade auriculate, Leaf blades 2-10 mm wide, Leaf blades 1-2 cm wide, Leaf blades mostly flat, Leaf blades mostly glabrous, Leaf blades scabrous, roughened, or wrinkled, Leaf blades glaucous, blue-green, or grey, or with white glands, Ligule present, Ligule a fringed, ciliate, or lobed membrane, Ligule a fringe of hairs, Inflorescence terminal, Inflorescence an open panicle, openly paniculate, branches spreading, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence branches more than 10 to numerous, Flowers bisexual, Flowers unisexual, Spikelets pedicellate, Spikelets sessile or subsessile, Spikelets dorsally compressed or terete, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, Spikelets with 2 fl orets, Spikelets solitary at rachis nodes, Spikelets bisexual, Spikelets disarticulating above the glumes, glumes persistent, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes equal or subequal, Glumes equal to or longer than adjacent lemma, Glumes 3 nerved, Glumes 4-7 nerved, Glumes 8-15 nerved, Lemmas thin, chartaceous, hyaline, cartilaginous, or membranous, Lemma similar in texture to glumes, Lemma 5-7 nerved, Lemma body or surface hairy, Lemma apex truncate, rounded, or obtuse, Lemma awnless, Lemma margins thin, lying flat, Lemma straight, Palea present, well developed, Palea membranous, hyaline, Palea longer than lemma, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - caryopsis.