Conferva flexuosa O.F. Müller, 1782: 5, pl. 882 (type locality: Denmark).
Cladophora flexuosa (O.F. Müller) Kützing, 1843b: 270.—Allender, 1981: 19, 20, 22.— Kendrick, Walker, & McComb, 1988: table 1.— Kendrick, Huisman, & Walker, 1990: 49.— Cambridge, Breeman, & van den Hoek, 1991: 81, figs. 1, 2, table 1.
Taxonomic synonym:
Conferva gracilis Griffiths ex Harvey, 1834b: 304, nom. illeg. (lectotype locality: Torbay, Devon, England fide van den Hoek, 1963: 77).
Cladophora gracilis Kützing, 1845: 215.—Raghukumar, 1987a: table 1.
INDIAN OCEAN DISTRIBUTION: Australia, India.
Note: In two treatises on European Cladophora published in the same year, C. flexuosa was considered a taxonomic synonym of C. sericea (Hudson) Kützing by van den Hoek (1963: 77), but was recognized as an independent species by Söderström (1963: 90–106). Cladophora gracilis was also differently treated, being assigned to C. sericea by van den Hoek and to C. flexuosa by Söderström. Support for Söderström's position has recently come from DNA-DNA hybridization studies (Bot, Stam, et al., 1989). Conferva gracilis Griffiths ex Harvey, the intended basionym of Cladophora gracilis, is not priorable since it is a later homonym of Conferva gracilis Wulfen (1803) and Conferva gracilis (Vaucher) De Candolle (1805). (See Note to Chaetomorpha gracilis Kützing.) Cladophora gracilis Kützing is treated as a nomen novum in accordance with Art. 58.3.