*Alternanthera philoxeroides Griseb.

Flower clusters on long peduncles up to 3 cm long, 8–10 mm diam. Perianth segments c. 4 mm long, without conspicuous points. Leaves obovate to narrow-elliptic, 3–6 cm long, 1–15 mm wide. Prostrate herb often forming dense mats and rooting at the nodes. Lower Hunter River Valley; Cumberland Plain. Ditches and wet places, often in slowly moving water. Introd. from S. America. Alligator Weed