Polysiphonia bicornis Sonder, 1880: 35 (intended type locality: Cape Leeuwin, Western Australia).
INDIAN OCEAN DISTRIBUTION: Australia.
Note: This name, without a description, appeared in a list of Australian algae. Polysiphonia bicornis was subsequently applied validly to a different species by Ohta (1973: 26, figs. 19, 20; type locality: Hamana near Imabetsu, Aomori Prefecture, Japan).