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Eragrostis

Eragrostis Gen. Pl. 23 (1776).

Derivation:. From Greek eros (love) and agrostis (grass), referring to the elegant spikelets.

Taxonomic revisions, nomenclatural references:. S.D.Koch, Rhodora 80: 390–403 (1978); M.Lazarides, Aust. Syst. Bot.10: 77–187 (1996).

Key references (keys and floras):. G.Bentham, Flora Australiensis 7: 641–650 (1878); C.A.Gardner, Flora of Western Australia 1 Gramineae 113–128 (1952); E.E.Henty, Manual Grasses New Guinea 89, 92–93, 96 (1969); M.Lazarides, Tropical Grasses S.E.Asia 173–176 (1980); M.Lazarides, Flora of Central Australia 456–461 (1981); J.C.Tothill and J.B.Hacker, Grasses of Southern Queensland 228–232 (1983); M.Lazarides, Flora of South Australia 4: 1934–1948 (1986); M.Lazarides, F.Quinn and J.Palmer, Flora of the Kimberley Region 1162–1166 (1992); B.K.Simon, Key to Australian Grasses 111–116 (1993); S.W.L.Jacobs and K.L.McClay, Flora of New South Wales 4: 532–544(1993); N.G.Walsh, Flora of Victoria 2: 560–568 (1994); D.I.Morris, Student's Flora of Tasmania 4B: 324–327 (1994); E.Edgar and H.E.Connor, Flora of New Zealand 5: 524–530 (2000); D.Sharp and B.K.Simon, AusGrass (2002); K.Mallet (ed.), Flora of Australia 44B: Poaceae 3: 346–409 (2005); J.P.Jessop, Grasses of South Australia 360–384 (2006); S.W.L.Jacobs, R.D.B.Whalley & D.J.B.Wheeler, Grasses of New South Wales, 4th ed, 245–258 (2008).

W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (356).

Native and naturalised. About 350 species, from cosmopolitan regions, mostly subtropical. About 73 species in Australia, WA, NT, SA, Qld, NSW, Vic, and Tas. Also New Guinea, Malesia and New Zealand.

Habit. Annual or perennial, tufted (sometimes shrubby) or decumbent or stoloniferous (rarely). Culms herbaceous (usually), or woody and persistent (occasionally). Leaf blades broad to narrow. Ligule a fringed membrane to a fringe of hairs. Hidden cleistogenes when present, in leaf sheaths.

Inflorescence. Inflorescence a false spike, with spikelets on contracted axes (occasionally) or paniculate (often with multicellular glands, characteristically scented), an open panicle with branches ending in single spikelets or a racemose panicle with spikelets all similar, open or contracted.

Spikelets. Spikelets laterally compressed (usually strongly so) or subterete, more than 2 flowered, with 2 or more fertile florets, solitary, subsessile or pedicelled; with naked rachilla extension. Fertile spikelets disarticulating above glumes (usually) or falling with glumes (in some species), with conventional internode spacings.

Glumes. Glumes unequal to more or less equal, shorter than spikelet, shorter than adjacent lemmas, pointed, awnless, keeled, similar (membranous). Lower glume 1 nerved. Upper glume 1 nerved.

Florets. Fertile florets (2–)3–45(–100). Lemmas similar in texture to glumes to decidedly firmer than glumes (narrow, membranous to papery), not becoming indurated, entire at apex or incised, muticous or mucronate (very rarely almost awned), without a germination flap, (1–)3 nerved, glabrous (usually glabrous), not keeled (wingless) or 1 keeled. Keel when present, wingless. Palea relatively long (but shorter than the lemma) or conspicuous and relatively short, thinner than lemma (membranous/hyaline), 2 nerved. Palea keels winged (rarely) or wingless, hairy (usually) or glabrous to scabrous. Callus absent (usually) or short, when present, blunt or persistent or deciduous. Lodicules when present, 2. Stamens 1–3. Grain small, compressed laterally, smooth or sculptured (sometimes finely striate or reticulate). Hilum short. Embryo large.

Kranz Anatomy. C4 (with the startling exception of E. walteri from Namibia), biochemical type NAD-ME (14 species).

2n = 20, 40, 50, 60, 80, 100, and 108, 2, 4, 5, 6, 8, and 10 ploid, commonly adventive.

Habitat. Helophytic (rarely), mesophytic, xerophytic. Often on poor or sandy soils or disturbed ground. Mostly species of open habitats.

Classification. Chloridoideae; Cynodonteae.

Notes. A large and variable genus, recognised by its paniculate inflorescence and glabrous entire lemma, but this circumscription needs some qualification. Some species are very close to Sporobolus, and it is evident that the distinction between the two genera is not as great as has been supposed (Clayton and Renvoize, 1986).

Types Species. E. eragrostis (L.) Wolf = E. minor Host.

Biogeographic Element. Clifford & Simon 1981, Simon & Jacobs 1990: Gondwanan.

Eremochloa Pl. Jungh. 357 (1854).

Derivation:. From Greek eremos (solitary) and chloa (grass), alluding to the single terminal spike.

Taxonomic revisions, nomenclatural references:. N.L.Bor, Kew Bull. 7:309–317 (1952); N.L.Bor, Grasses of Burma, Ceylon, India and Pakistan (excluding Bambuseae) 145–148 (1960); A.G.Buitenhuis & J.F.Veldkamp, Blumea 46: 399–420 (2001).

Key references (keys and floras):. J.W.Vickery, Flora of New South Wales, Gramineae 19: 22–23 (1961); E.E.Henty, Manual Grasses New Guinea 96–97 (1969); M.Lazarides, Tropical Grasses S.E.Asia 36–37 (1980); J.C.Tothill and J.B.Hacker, Grasses of Southern Queensland 234–235 (1983); B.K.Simon, Key to Australian Grasses 116 (1993); S.W.L.Jacobs and C.A.Wall, Flora of New South Wales 4: 431–432 (1993); D.Sharp and B.K.Simon, AusGrass (2002); S.W.L.Jacobs, R.D.B.Whalley & D.J.B.Wheeler, Grasses of New South Wales, 4th ed, 259 (2008).

W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (633).

Native. 9 species, from India, Sri Lanka, southern China, southeast Asia and Australia. 3 species in Australia, Qld and NSW. Also New Guinea and Malesia.

Habit. Perennial, tufted. Leaf blades narrow. Ligule an unfringed membrane.

Inflorescence. Inflorescence a single raceme (comprising axillary or terminal spike-like, slender flattened racemes), a single raceme or spike. Spikelet-bearing axes spikelike (exserted on long slender peduncles, curved, with imbricate spikelets), with heteromorphic spikelets (the pedicelled spikelets very reduced), solitary, with spikelets in pairs, one sessile, the other pedicelled, disarticulating at joints. Internodes with a basal callus-knob, densely long-hairy to somewhat hairy.

Spikelets. Spikelets all partially embedded in rachis, dorsally compressed, 2 flowered, with 1 fertile floret, paired, sessile and pedicelled, in pedicelled/sessile combinations; sessile spikelet with lower incomplete floret. Fertile spikelets falling with glumes (and with the adjacent internode and pedicel).

Glumes. Glumes unequal, (the longer) long relative to adjacent lemmas, awnless, dissimilar (the lower 2-keeled and spiny on the margins, the upper naviculate, smooth, glabrous). Lower glume two-keeled, prickly (the lower keels with filiform or flattened scabrid curved or horizontal spines), 5–9 nerved. Upper glume 3 nerved.

Florets. Lower incomplete floret(s) male. Lemmas awnless, more or less equalling fertile lemmas to exceeding fertile lemmas, similar in texture to fertile lemmas (hyaline), not becoming indurated. Fertile florets 1. Lemmas less firm than glumes (hyaline), not becoming indurated, entire at apex, pointed, muticous, 0 nerved, glabrous. Palea textured like lemma (hyaline), nerveless. Lodicules 2. Stamens 3. Grain small, compressed dorsiventrally. Hilum short. Embryo large. Pedicels free of rachis (flattened). Pedicelled spikelets much reduced (to a single glume).

Kranz Anatomy. C4.

2n = 18, 2 ploid.

Habitat. Mesophytic. Short grassland. Species of open habitats.

Classification. Panicoideae; Andropogoneae.

Notes. A homogeneous genus related to Coelorachis (=Mnesithea) (Clayton and Renvoize, 1986).

Types Species. E. horneri Buse = E. ciliaris (L.) Merr.

Biogeographic Element. Clifford & Simon 1981, Simon & Jacobs 1990: Indo-Malayan.

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