Coelachne Prodr. 187 (1810).

Derivation:. From Greek koilos (hollow) and achne (glume), as the glumes are hollow.

Key references (keys and floras):. G.Bentham, Flora Australiensis 7: 625–626 (1878); E.E.Henty, Manual Grasses New Guinea 51 (1969); M.Lazarides, Tropical Grasses S.E. Asia 87–88 (1980); R.D.Webster, Australian Paniceae 33–34 (1987); B.K.Simon, Key to Australian Grasses 86 (1993);; D.Sharp and B.K.Simon, AusGrass (2002).

W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (549).

Native. 10 species, from Old World tropics. 1 species in Australia, NT and Qld. Also New Guinea and Malesia.

Habit. Low annual or perennial, tufted or decumbent. Leaf blades narrow. Ligule a fringe of hairs.

Inflorescence. Inflorescence of spicate main branches or paniculate, a spike-like panicle or an open panicle with branches ending in single spikelets, open or contracted.

Spikelets. Spikelets subterete to dorsally compressed, 2 flowered, with 2 or more fertile florets, solitary or paired, pedicelled. Fertile spikelets ovate, disarticulating above glumes, with distinctly elongated rachilla internodes between florets.

Glumes. Glumes unequal to more or less equal, shorter than spikelet (1/3 to 2/3 their length), shorter than adjacent lemmas, hairless, obtuse, awnless, non-keeled, similar (broad, membranous). Lower glume 1–5 nerved. Upper glume 3–7 nerved.

Florets. Fertile florets 2 (dissimilar, separated by a slender rachilla segment). Lemmas decidedly firmer than glumes (the lower becoming somewhat hardened, the upper remaining membranous), smooth, not becoming indurated, white in fruit, entire at apex, blunt, muticous (obtuse), with a clear germination flap, 0 nerved, hairy (upper lemma usually pubescent) or glabrous (lower lemma basally hairy or not). Palea entire (obtuse), 2 nerved. Lodicules 2. Stamens 1–3. Grain small, compressed dorsiventrally. Hilum short. Embryo large or small.

Kranz Anatomy. C3.

2n = 40.

Habitat. Helophytic. Streamsides and marshes. Species of open habitats.

Classification. Panicoideae; Isachneae.

Notes. A homogeneous genus of barely separable species (Clayton and Renvoize, 1986).

Types Species. C. pulchella R.Br.

Biogeographic Element. Clifford & Simon 1981, Simon & Jacobs 1990: Old World Tropics.

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith