Microlaena Prodr. 208 (1810).
Derivation:. From Greek mikros (small) and laina (cloak), alluding to the two minute glumes.
Taxonomic revisions, nomenclatural references:. L.P.M.Willemse, Blumea 28: 181–194 (1982) under Ehrharta.
Key references (keys and floras):. G.Bentham, Flora Australiensis 7: 552–553 (1878); C.A.Gardner, Flora of Western Australia 1 Gramineae 14–16 (1952); E.E.Henty, Manual Grasses New Guinea 124–125(1969); J.W.Vickery, Flora of New South Wales, Gramineae 19:297–300 (1975); M.Lazarides, Tropical Grasses S.E. Asia 186–187 (1980); J.C.Tothill and J.B.Hacker, Grasses of Southern Queensland 308–309 (1983); J.P.Jessop, Flora of South Australia 4: 1838 (1986); B.K.Simon, Key to Australian Grasses 131–132 (1993); S.W.L.Jacobs and S.M.Hastings, Flora of New South Wales 4: 654 (1993); N.G.Walsh, Flora of Victoria 2: 369 (1994); E.Edgar and H.E.Connor, Flora of New Zealand 5: 44–52 (2000); D.Sharp and B.K.Simon, AusGrass (2002); J.P.Jessop, Grasses of South Australia 58–58 (2006); A.Wilson (ed.), Flora of Australia 44A: Poaceae 2: 380–384 (2009).
W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (syn. of Erharta).
Native. 10 species, from Philippines, Java to Australasia. 2 species in Australia, WA, SA, Qld, NSW, Vic, and Tas. Also New Guinea, Malesia and New Zealand.
Habit. Perennial, stoloniferous and tufted. Culms woody and persistent, or herbaceous. Leaf blades narrow. Ligule an unfringed membrane to a fringed membrane (a hyaline rim, with caducous cilia). Hidden cleistogenes when present, in leaf sheaths.
Inflorescence. Inflorescence a single raceme or paniculate, a spike-like panicle, open.
Spikelets. Spikelets laterally compressed, more than 2 flowered, with 1 fertile floret, awned, solitary, pedicelled; with rachilla terminating in a floret. Fertile spikelets with lower incomplete floret(s), disarticulating above glumes, with a distinctly elongated rachilla internode above glumes (i.e., beneath the empty lemmas).
Glumes. Glumes very minute, unequal (the u.g. longer), shorter than adjacent lemmas, awnless, similar (membranous). Lower glume 0–1 nerved. Upper glume 0–1 nerved.
Florets. Lower incomplete floret(s) sterile. Lemmas awned (long acuminate, tapered into long slender awns), 5–9 nerved, exceeding fertile lemmas, decidedly firmer than fertile lemmas (cartilaginous, usually ribbed and grooved). Fertile florets 1. Lemmas decidedly firmer than glumes (cartilaginous, with thin margins), becoming indurated to not becoming indurated, entire at apex, pointed, muticous or mucronate or awned (tapered into the stout awn), 5–7 nerved, glabrous, 1 keeled (scabrid-ciliate on the keel). Awns (when present) 1, apical, non-geniculate, hairless (scabrid), much shorter than body of lemma. Palea when present relatively long or conspicuous and relatively short or very reduced, entire, thinner than lemma, 1 nerved (or nerveless), one keeled or not keeled. Palea keels wingless. Lodicules 2. Stamens 1–6. Grain medium sized, oblong-linear, compressed laterally. Hilum long-linear. Embryo small.
Kranz Anatomy. C3.
Habitat. Helophytic to mesophytic. Shade species and species of open habitats.
Classification. Ehrhartoideae; Ehrharteae.
Notes. Placed in synonymy with Ehrharta (Clayton and Renvoize, 1986). Recent cladistic studies (Verboom pers. com.) justifies the recognition of the narrowly circumscribed genera Ehrharta, Microlaena and Tetrarrhena, retained in this treatment (B.K.Simon).
Types Species. M. stipoides (Labill.) R.Br.
Biogeographic Element. Clifford & Simon 1981, Simon & Jacobs 1990: Indo-Malayan.