Dimeria Prodr. 204 (1810).

Derivation:. From the Latin dimerous (of two parts), alluding to the two spikes.

Taxonomic revisions, nomenclatural references:. N.L. Bor, Kew Bull. 10: 553–592 (1952).

Key references (keys and floras):. G.Bentham, Flora Australiensis 7: 522–523(1878); E.E.Henty, Manual Grasses New Guinea 80–81 (1969); M.Lazarides, Tropical Grasses S.E. Asia 34–35 (1980); B.K.Simon, Flora of the Kimberley Region 1150 (1992); B.K.Simon, Key to Australian Grasses 103 (1993); D.Sharp and B.K.Simon, AusGrass (2002).

W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (605).

Native. 40 species, from Mascarene Is., southeast Asia, the Indomalayan region, Australia and Polynesia. 3 species in Australia, WA, NT, and Qld. Also New Guinea and Malesia.

Habit. Annual or perennial (often pigmented when mature), tufted. Leaf blades narrow. Ligule an unfringed membrane.

Inflorescence. Inflorescence of spicate main branches or a single raceme (the raceme or racemes spiciform), of digitate or subdigitate racemes or spikes, when of more than one raceme, digitate. Spikelet-bearing axes racemes.

Spikelets. Spikelets all partially embedded in rachis, 2 flowered, with 1 fertile floret (upper floret), solitary, shortly pedicelled (the pedicels usually but not always shortly clavate). Fertile spikelets strongly laterally compressed, falling with glumes or not disarticulating (D. woodrowii).

Glumes. Glumes more or less equal, awnless, keeled, with keel conspicuously winged or without a median keel-wing, similar. Lower glume relatively smooth, 1–3 nerved. Upper glume 1–3 nerved.

Florets. Lower incomplete floret(s) sterile. Lemmas awnless, 0 nerved, similar in texture to fertile lemmas (thinly membranous to hyaline). Fertile florets 1. Lemmas less firm than glumes, not becoming indurated, incised (or rarely entire), muticous or awned, without a germination flap, 1–3 nerved, glabrous. Awns when present 1, usually from a sinus, geniculate, hairless (glabrous), much longer than body of lemma. Palea absent. Stamens usually 2 (the filaments short). Grain small, compressed laterally (linear). Hilum short (elliptical). Embryo large.

Kranz Anatomy. C4.

2n = 14.

Habitat. Mesophytic. Forest glades and margins. Species of open habitats.

Classification. Panicoideae; Andropogoneae.

Notes. A homogeneous genus with many, perhaps too many, narrowly defined species (Clayton and Renvoize, 1986).

Types Species. D. acinaciformis R.Br.

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

AVH 2011

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