Micraira Fragm. 5: 208 (1866).
Derivation:. From Greek mikros (small) and the genus Aira, bacuse of resemblance on a smaller scale to that genus.
Taxonomic revisions, nomenclatural references:. M.Lazarides, Brunonia 2: 67–84 (1979) and Nuytsia 5: 290–296 (1985).
Key references (keys and floras):. G.Bentham, Flora Australiensis 7: 624 (1878); J.C.Tothill and J.B.Hacker, Grasses of Southern Queensland 306–307 (1983); E.M.Bennett, Flora of the Kimberley Region 1188–1190 (1992); B.K.Simon, Key to Australian Grasses 130–131 (1993); D.Sharp and B.K.Simon, AusGrass (2002); K.Mallet (ed.), Flora of Australia 44B: Poaceae 3: 120–131 (2005).
W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (296).
Native, endemic. 14 species. WA, NT, and Qld.
Habit. Perennial (moss-like in appearance), mat-forming. Leaves spirally disposed. Leaf blades narrow, cordate or not cordate. Ligule a fringed membrane to a fringe of hairs.
Inflorescence. Inflorescence a single spike or a single raceme or paniculate, an open panicle with branches ending in single spikelets, open or contracted.
Spikelets. Spikelets laterally compressed, 2 flowered, with 2 or more fertile florets, solitary, pedicelled; with naked rachilla extension. Fertile spikelets with lower incomplete floret(s) or without lower incomplete floret(s), disarticulating above glumes.
Glumes. Glumes more or less equal, shorter than spikelet to exceeding florets, shorter than adjacent lemmas to long relative to adjacent lemmas, pointed, awnless (muticous, mucronate or mucronulate), similar (membranous). Lower glume 1 nerved. Upper glume 1 nerved.
Florets. Lower incomplete floret(s) male, or sterile. Lemmas awnless, 5–9 nerved, more or less equalling fertile lemmas, similar in texture to fertile lemmas, not becoming indurated. Fertile florets 1–2. Lemmas almost rectangular, less firm than glumes (thinly membranous to hyaline), not becoming indurated, entire at apex, blunt, muticous, 5–9 nerved, glabrous, 1 keeled to not keeled. Palea relatively long or conspicuous and relatively short or very reduced (almost rectangular), entire to deeply bifid, thinner than lemma to textured like lemma, 2 nerved or several nerved (2, or 5–7). Stamens 1. Grain small, ellipsoid, compressed dorsiventrally. Hilum long-linear. Embryo small.
Kranz Anatomy. C3.
Habitat. Rocky places, in shallow soils.
Classification. Micrairoideae; Micraireae.
Notes. With the exception of M. subulifolia, which is confined to Queensland, all the species are distributed in a relatively small area of the Northern Territory and Western Australia. Characteristically plants of the species grow in localised colonies in highly specific habitats. The genus is notable for prominent features such as spiral phyllotaxy, mat-forming habit, and an unusual 2-keeled and many nerved or nerveless palea which is usually divided into 2 equal parts. A noteworthy physiological feature is the ability of plants to revive after dehydration (i.e. they are resurrection plants). M. subulifolia is isolated in terms of morpholgy, distribution and ecology (Lazarides, 1985). The genus is isolated from all others taxonomically and may deserve placement in a separate subfamily. However, pending futher analyses, they are presently placed as Incertae Sedis (Kellogg, pers. com.).
Types Species. M. subulifolia F. Muell.
Biogeographic Element. Clifford & Simon 1981, Simon & Jacobs 1990: Endemic.