Gastridium* Ess. Agrostogr. 21, t. 6, fig. 6 (1812).
Derivation:. Diminutive of the Greek gaster (belly) referring to the basally swollen glumes.
Key references (keys and floras):. C.A.Gardner, Flora of Western Australia 1 Gramineae 147–150 (1952); J.P.Jessop, Flora of South Australia 4: 1921 (1986); B.K.Simon, Key to Australian Grasses 122 (1993); S.W.L.Jacobs and K.L.McClay, Flora of New South Wales 4: 568 (1993); N.G. Walsh, Flora of Victoria 2: 495–496 (1994); D.I.Morris, Student's Flora of Tasmania 4B: 280–281 (1994); E.Edgar and H.E.Connor, Flora of New Zealand 5: 264–265 (2000); D.Sharp and B.K.Simon, AusGrass (2002); J.P.Jessop, Grasses of South Australia 222 (2006); S.W.L.Jacobs, R.D.B.Whalley & D.J.B.Wheeler, Grasses of New South Wales, 4th ed, 269 (2008);A.Wilson (ed.), Flora of Australia 44A: Poaceae 2: 238–240 (2009).
W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (206).
Naturalised. 2 species, from Canaries, western Europe, Mediterranean. 2 species in Australia, WA, SA, NSW, Vic, and Tas. Also New Zealand.
Habit. Annual, tufted (or the culms solitary). Leaf blades narrow. Ligule an unfringed membrane.
Inflorescence. Inflorescence paniculate.
Spikelets. Spikelets laterally compressed, pedicelled; shortly with naked rachilla extension (or rarely not prolonged?). Fertile spikelets laterally compressed, disarticulating above glumes.
Glumes. Glumes exceeding florets, long relative to adjacent lemmas (the floret enclosed by their swollen bases), conspicuously ventricose, pointed (acuminate), awnless, keeled, similar (swollen, globular and more or less cartilaginous at the base, membranous above). Lower glume 1 nerved. Upper glume 1 nerved.
Florets. Fertile florets 1. Lemmas less firm than glumes, incised (more or less dentate), mucronate to awned (the midvein usually excurrent), 5 nerved, not keeled. Awns when present, 1, dorsal, geniculate, much shorter than body of lemma to much longer than body of lemma. Palea relatively long, apically notched, 2 nerved, 2 keeled. Callus short, blunt. Lodicules 2. Stamens 3. Stigmas 2. Grain small, compressed dorsiventrally (slightly). Hilum short. Embryo small. Endosperm hard.
Kranz Anatomy. C3.
2n = 14 and 28, 2 ploid, commonly adventive.
Habitat. Mesophytic to xerophytic. Grassy places and arable land. Species of open habitats.
Classification. Pooideae; Poeae.
Notes. Linked to Agrostis through Triplachne (Clayton & Renvoize, 1986).
Types Species. G. australe P.Beauv., nom. illeg..
Biogeographic Element. Clifford & Simon 1981, Simon & Jacobs 1990: Naturalised.