Paspalum distichum
L. Water CouchSemi-aquatic, long-rhizomatous and stoloniferous perennial. Culms erect or ascending, to c. 60 cm high; nodes of prostrate stems often hairy. Leaves mostly distichous; blade flat, to 20 cm long and 7 mm wide, glabrous or ciliate along margins near base; sheath ciliate along margins; ligule truncate, c. 1 mm long. Panicle forked, racemes 2–6 cm long. Spikelets shortly pedicellate, in two rows, elliptic, 2.5–3.5 mm long, acute; lower glume absent or rudimentary, to c. 1 (rarely to 2) mm long; upper glume 3–6-nerved (mid-vein sometimes developed) as long as spikelet, sparsely covered with fine appressed hairs; lower lemma 3–5-nerved, equal to upper glume; fertile lemma slightly shorter than spikelet, slightly rounded dorsally, firm, smooth or minutely ridged longitudinally. Flowers Feb.–May.
MuM, Wim, GleP, Brid, VVP, VRiv, MSB, RobP, MuF, GipP, OtP, WaP, Gold, CVU, DunT, NIS, EGL, EGU, WPro, HSF, HNF, OtR, Strz. Naturalized in all States except NT, Tas. Native in many tropical and warm-temperate countries, but apparently introduced in Australia. Fairly common, bordering rivers, marshes, swamps and on well-watered, cultivated land. Generally found in or near fresh water, but tolerates a degree of brackishness.
Sometimes considered native in Victoria (and some other parts of Australia), but its restriction to mainly disturbed habitats and its otherwise near-tropical known natural occurrence strongly suggests that it is an introduction here.
Walsh, N.G. (1994). Poaceae. In: Walsh, N.G.; Entwisle, T.J., Flora of Victoria Vol. 2, Ferns and Allied Plants, Conifers and Monocotyledons, pp. 356–627. Inkata Press, Melbourne.