Brachyachne Hooker's Icon. Pl. Tab. 3099 (1922).
Derivation:. From Greek brachys (short) and achne (glume), alluding to the lemma or flowering glume being shorter than the two outer glumes.
Taxonomic revisions, nomenclatural references:. M.Lazarides, Austr. J. Bot. Supp. Ser. 5: 41–48 (1972).
Key references (keys and floras):. G.Bentham, Flora Australiensis 7: 609–610(1878) as Cynodon in part; C.A.Gardner, Flora of Western Australia 1 Gramineae 212–214 (1952); E.E.Henty, Manual Grasses New Guinea 42 (1969); M.Lazarides, Tropical Grasses S.E.Asia 157 (1980); M.Lazarides, Flora of Central Australia 466–467 (1981); J.C.Tothill and J.B.Hacker, Grasses of Southern Queensland 136–137 (1983); J.P.Jessop, Flora of South Australia 4: 1950 (1986); M.Lazarides, F.Quinn and J.Palmer, Flora of the Kimberley Region 1131,1133 (1992); B.K.Simon, Key to Australian Grasses 79–80 (1993); S.W.L.Jacobs and S.M.Hastings, Flora of New South Wales 4: 522–523 (1993); D.Sharp and B.K.Simon, AusGrass (2002); K.Mallet (ed.), Flora of Australia 44B: Poaceae 3: 294–300 (2005); J.P.Jessop, Grasses of South Australia 341–343 (2006); S.W.L.Jacobs, R.D.B.Whalley & D.J.B.Wheeler, Grasses of New South Wales, 4th Ed, 170 (2008).
W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (411).
Native or naturalised. 10 species, from Africa, Java to Australia. 5 species in Australia (1 introduced), WA, NT, SA, Qld, and NSW. Also New Guinea and Malesia.
Habit. Annual or perennial, stoloniferous or tufted. Leaf blades narrow. Ligule a fringed membrane to a fringe of hairs.
Inflorescence. Inflorescence of spicate main branches (usually, occasionally the racemes single), of digitate racemes or spikes, digitate.
Spikelets. Spikelets 1 flowered to 2 flowered, with 1 fertile floret, solitary (appressed), subsessile (on one side of inflorescence axis); usually with naked rachilla extension. Fertile spikelets adaxial (with lower glume against rachis), strongly laterally compressed, disarticulating above glumes.
Glumes. Glumes more or less equal, exceeding florets (enclosing the floret), long relative to adjacent lemmas, blunt, awnless, keeled, dissimilar (broad, usually thinly leathery, the the lower curved, the upper straight). Lower glume 1 nerved. Upper glume 1 nerved.
Florets. Fertile florets 1. Lemmas less firm than glumes to similar in texture to glumes (membranous to hyaline), not becoming indurated, entire at apex or incised, when entire, pointed or blunt, muticous or mucronate (rarely), 3 nerved, hairy (long-haired on the nerves or all over), 1 keeled (folded along the mid-nerve). Palea relatively long to conspicuous and relatively short, textured like lemma, 2 nerved (with long hairs). Callus short, pointed or blunt. Lodicules 2. Stamens 3. Grain small, ellipsoid, compressed laterally. Hilum short. Embryo large.
Kranz Anatomy. C4.
Habitat. Helophytic to mesophytic. Seasonal swamps and moist rock crevices. Species of open habitats.
Classification. Chloridoideae; Cynodonteae.
Notes. The flat spikelets indicate a derivation from Cynodon. Brachyachne ciliaris and B. prostrata verge towards Microchloa, although easily distinguishable by their digitate racemes and flat rachis (Clayton and Renvoize, 1986).
Types Species. B. convergens (F.Muell.)Stapf.
Biogeographic Element. Clifford & Simon 1981, Simon & Jacobs 1990: Old World Tropics.