Potamophila Prodr. 211 (1810).

Derivation:. From the Greek potamos (river) and philus (loving), alluding to the habitat of the only species.

Key references (keys and floras):. G.Bentham, Flora Australiensis 7: 550(1878); B.K.Simon, Key to Australian Grasses 152 (1993); S.W.L.Jacobs and S.M.Hastings, Flora of New South Wales 4: 652 (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, 357 (2008); A.Wilson (ed.), Flora of Australia 44A: Poaceae 2: 369 (2009)

W.D.Clayton & S.A.Renvoize, Genera Graminum (1986), genus (78).

Native, endemic. 1 species. NSW.

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

Inflorescence. Inflorescence paniculate.

Spikelets. Spikelets strongly laterally compressed, more than 2 flowered (with 3 florets, the 2 proximal ones sterile), pedicelled; with rachilla terminating in a floret; sessile spikelet with lower incomplete floret. Fertile spikelets unconventional (by virtue of reduced glumes, cf. Oryza), strongly laterally compressed, disarticulating above glumes.

Glumes. Glumes if considered present, two, if considered present, relatively large, more or less equal, shorter than adjacent lemmas, awnless. Lower glume 0 nerved. Upper glume 0 nerved.

Florets. Lower incomplete floret(s) sterile. Lemmas ovate, awnless, 0 nerved, exceeded by fertile lemmas (very small, less than 1/8 to 1/4 the spikelet length), less firm than fertile lemmas to similar in texture to fertile lemmas (membranous), not becoming indurated. Fertile florets 1. Lemmas membranous or thinly chartaceous, entire at apex, pointed to blunt, muticous, 5 nerved, not keeled (‘sub-keeled’). Palea relatively long, entire, textured like lemma, several nerved (3-nerved), one keeled. Lodicules 2. Stamens 6. Stigmas 2. Grain compressed dorsiventrally to terete. Hilum long-linear. Embryo small.

Kranz Anatomy. C3.

Habitat. Helophytic.

Classification. Ehrhartoideae; Oryzeae.

Notes. Confined to the rivers of northern New South Wales. The spikelets have a similar appearance to other small oryzoid genera, Maltebrunia from tropical Africa and Madagascar and Prosphytochloa from South Africa (B.K.Simon).

Types Species. P. parviflora R.Br.

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

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