Perotis Hortus Kew. 1: 85 (1789).
Derivation:. From Greek peri (around) and otites (eared), referring to the long awns surrounding the spikelets.
Taxonomic revisions, nomenclatural references:. J.F.Veldkamp and H. van Steenbergen, Austrobaileya 3: 609–614 (1992).
Key references (keys and floras):. G.Bentham, Flora Australiensis 7: 509 (1878); C.A.Gardner, Flora of Western Australia 1 Gramineae 186(1952); E.E.Henty, Manual Grasses New Guinea 148 (1969); J.W.Vickery, Flora of New South Wales, Gramineae 19: 303–305 (1975); M.Lazarides, Tropical Grasses S.E. Asia 194–195 (1980); M.Lazarides, Flora of Central Australia 469–470 (1981); J.C.Tothill and J.B.Hacker, Grasses of Southern Queensland 340–341(1983); J.P.Jessop, Flora of South Australia 4:1957 (1986); M.Lazarides, F.Quinn and J.Palmer, Flora of the Kimberley Region 1204, 1206 (1992); B.K.Simon, Key to Australian Grasses 143 (1993); D.Sharp and B.K.Simon, AusGrass (2002); J.P.Jessop, Grasses of South Australia 393 (2006); K.Mallet (ed.), Flora of Australia 44B: Poaceae 3: 265–268 (2005); S.W.L.Jacobs, R.D.B.Whalley & D.J.B.Wheeler, Grasses of New South Wales, 4th ed, 336 (2008).
W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (441).
Native. 10 species, from Africa, India, Ceylon, eastern Asia, Australia. 3 species in Australia, WA, NT, SA, Qld, and NSW. Also New Guinea and Malesia.
Habit. Annual or perennial (rarely), tufted. Leaf blades narrow (but relatively broad at the base). Ligule an unfringed membrane to a fringed membrane.
Inflorescence. Inflorescence a single spike or a single raceme (a narrow `bottlebrush', bearded by the long glume awns), a single raceme or spike.
Spikelets. Spikelets laterally compressed, 1 flowered, with 1 fertile floret, awned, solitary (often reflexing when mature), subsessile to pedicelled; with rachilla terminating in a floret. Fertile spikelets falling with glumes.
Glumes. Glumes more or less equal, long relative to adjacent lemmas (considerably exceeding them), hairy (often) or hairless, awned, keeled, similar (narrow, membranous to cartilaginous, tipped by long capillary awns). Lower glume 1 nerved. Upper glume 1 nerved.
Florets. Fertile florets 1. Lemmas lanceolate, less firm than glumes (hyaline), not becoming indurated, entire at apex, pointed or blunt, muticous, 1 nerved, glabrous, 1 keeled. Palea conspicuous and relatively short (but almost equalling the lemma), nerveless. Lodicules 2. Stamens 3. Grain small to medium sized (almost as long as the glumes), longitudinally grooved, compressed dorsiventrally or terete. Hilum short. Embryo large.
Kranz Anatomy. C4.
2n = 36 or 40.
Habitat. Mesophytic, xerophytic. Savanna and grassland, often ruderal. Species of open habitats.
Classification. Chloridoideae; Cynodonteae.
Notes. A small genus of about 10 Old World tropical species. It has been regarded by some (Hubbard in Bor 1960) as belonging to a separate tribe, Perotideae, while others have included it within the Lappaginae (Pilger, 1956), Zoysieae (Jacques-Felix, 1962), or Cynodonteae-Zoysiinae (Clayton and Renvoize, 1986) (Veldkamp and van Steenbergen, 1992). The tribes of Chloridoideae as traditionally delimited, are artificial in that they have no phylogenetic basis (Kellogg pers. com.) .
Types Species. P. indica (L.) Kuntze.
Biogeographic Element. Clifford & Simon 1981, Simon & Jacobs 1990: Old World Tropics.