Potamogeton perfoliatus
Leaves narrow- to broad-ovate or almost orbicular, 1–4 cm long, cordate and stem-clasping, with 5–7 strong longitudinal veins and fainter intermediate veins. Spikes 1–2 cm long; peduncles longer than the leaves. Fruiting carpels scarcely beaked. Nepean River. Fl. spring–summer