P. tricarinatus tricarinatusP. tricarinatus F.Muell. & A.Benn. ex A.Benn.

Floating leaves cordate to elliptic-ovate, 5–10 cm long. Fruits c. 3 mm long, with 3 dorsal ridges. Spikes dense, 25–50 mm long, on rather stout peduncles. Floating leaves with 15–25 veins; submerged leaves narrow-lanceolate. Widespread. Fl. spring–autumn