Leersia Prodr.1: 21 (1788).
Derivation:.
Named for Johan Daniel Leers, a German apothecary and botanist of the
18th century.
Key references
(keys and floras):. G.Bentham, Flora Australiensis 7: 549 (1878);
E.E.Henty, Manual Grasses New Guinea 117 (1969); J.W.Vickery, Flora
of New South Wales, Gramineae 19: 273–276 (1975); M.Lazarides, Tropical
Grasses S.E. Asia 182–183 (1980); J.C.Tothill and J.B.Hacker, Grasses of
Southern Queensland 294–295 (1983); B.K.Simon, Key to Australian Grasses
128 (1993); S.W.L.Jacobs and S.M.Hastings, Flora of New South Wales 4:
650–651 (1993); N.G.Walsh, Flora of Victoria 2: 366 (1994); E.Edgar and
H.E.Connor, Flora of New Zealand 5: 57–58 (2000); 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, 292 (2008); A.Wilson (ed.), Flora of
Australia 44A: Poaceae 2: 360–361 (2009).
W.D.Clayton &
S.A.Renvoize, Genera Graminum (1986), genus (81).
Native and naturalised.
18 species, from tropical and warm temperate regions. 2 species in Australia,
NT, SA, Qld, NSW, and Vic. Also New Guinea, Malesia and New Zealand.
Habit. Annual
(rarely) or perennial, rhizomatous or stoloniferous or tufted. Leaf blades
narrow. Ligule an unfringed membrane. Hidden cleistogenes when present in leaf
sheaths.
Inflorescence.
Inflorescence paniculate or of spicate main branches (the primary branches
sometimes simple), an open panicle with branches ending in single spikelets,
open, non-digitate.
Spikelets.
Spikelets 1 flowered, with 1 fertile floret, solitary, pedicelled. Fertile
spikelets unconventional (the dilated pedicel apices may or may not represent
glumes), strongly laterally compressed, disarticulating above glumes (or at
least, above the rim assumed to represent them), with no more than a short
stipe beneath the floret.
Glumes. Glumes
absent (apparently represented by a narrow rim at the tip of the pedicel).
Florets.
Fertile florets 1. Lemmas not becoming indurated (membranous to papyraceous),
muticous to awned (often caudate), without a germination flap, 3–5 nerved,
usually hairy (hispid on the nerves), 1 keeled. Awns when present, 1, apical,
non-geniculate, much shorter than body of lemma to much longer than body of
lemma. Palea relatively long (but much narrower than the lemma), entire, tough,
several nerved (3), one keeled. Lodicules 2. Stamens 1–3 or 6. Grain small,
compressed laterally. Hilum long-linear. Embryo small.
Kranz Anatomy.
C3.
2n = 24,
48, and 60, 2, 4, and 5 ploid, commonly adventive.
Habitat.
Helophytic. Shade species and species of open habitats.
Classification.
Ehrhartoideae; Oryzeae.
Notes. The
genus is distinguished from Oryza only by the absence of sterile lemmas,
and is linked to Chikusichloa by the species with short stipitate
florets (Clayton and Renvoize, 1986).
Types Species. L.
oryzoides (L.) Sw.
Biogeographic
Element. Clifford & Simon 1981, Simon & Jacobs 1990: Gondwanan.
