Conferva simplex Wulfen, 1803: 17 (type locality: Trieste, Italy).
Digenea simplex (Wulfen) C. Agardh, 1822 [1822–1823]: 389.—Montagne & Millardet, 1862: 19.— J. Agardh, 1863 [1851–1863]: 845–846.— Dickie, 1874b: 192.— Dickie, 1877b: 6.— Askenasy, 1888: 49.— Hauck, 1888 [1886–1889]: 90.— Schmitz, 1895a: 140.— Schmitz, 1895b: 28.— Falkenberg, 1901: 159–163, pl. 9: figs. 25–29.— Piccone, 1901: 123.— De Toni, 1903: 963.— Lucas, 1909: 41.— De Toni & Forti, 1923: 41.— De Toni, 1924: 404.— Jadin, 1935: 169.— Børgesen, 1939b: 121.— Børgesen, 1945: 39–40.— Børgesen, 1953: 57–58.— Newton, 1955b: 143.— Isaac, 1956a: 189, fig. 21.— Kylin, 1956: 509.— Isaac, 1958: 20.— Pocock, 1958: 27.— Baissac, Lubet, & Michel, 1962: 262.— Hodgkin & Michel, 1963: 131.— V. May, 1965: 382.— Isaac, 1967: 81.— W. Isaac & F. Isaac, 1968: 25.— S. Dixit, 1970: 125.— Mshigeni, 1973: 35.— Saenger, 1974: 22, figs. 9, 10.— Jaasund, 1976: 125, fig. 254.— Jaasund, 1977b: 411.— Brown & Jarman, 1978: 1254.— Pichon, 1978: 176, 413.— Farghaly, 1980: 165.— Lawson, 1980: 41.— Seagrief, 1980: 27, fig. on pl. 11.— Aleem, 1984: 920.— Payri, 1985: 640.— Al-Hasan & W. Jones, 1989: 304, pl. 10: fig. 85.— Basson, Mohamed, & Arora, 1989: 38.— Heiba, 1989: 404, table 1.— Huisman et al., 1990: 97.— Kendrick, Huisman, & Walker, 1990: 48, 52.— Yarish & Wamukoya, 1990: table 2.— Basson, 1992: 227.— Jagtap, 1992: 57.— Jagtap, 1993: table I.— Naim, 1993: 141.— Al Easa, Kornprobst, & Rizk, 1995: 374.— van Oppen et al., 1995: 121.
Digenea wulfenii Kützing, 1843b: 433, nom. illeg.—Kützing, 1849: 841 (`wulfeni').— G. Martens, 1868: 98–99.
Taxonomic synonym:
* Fucus lycopodium Turner, 1811–1819: 6–7, pl. 199, nom. illeg. (syntype localities: Red Sea; Sri Lanka).
Caulerpa lycopodium C. Agardh, 1817: XXIII.
Cladostephus lycopodium (C. Agardh) C. Agardh, 1824: 168.—C. Agardh, 1828: 14–15.— Harvey, 1834a: 156.— J. Agardh, 1848b: 42–43.
INDIAN OCEAN DISTRIBUTION: Australia, Bahrain, Comoro Islands, Iran, Kenya, Kuwait, Madagascar, Mauritius, Mozambique, Nicobar Islands, Qatar, Réunion, Rodriguez Island, Somalia, South Africa, Sri Lanka, Tanzania.
Note: The synonymy was proposed by J. Agardh (1863 [1851–1863]: 845–846). Stackhouse (1801 [1795–1801]: 107, pl. XVII, in part) illustrated an alga that he associated with Fucus lycopodioides Linnaeus (1767a: 717) (Rhodomela lycopodioides (Linnaeus) C. Agardh), but which in fact is probably Cladostephus spongiosus (Hudson) C. Agardh. Stackhouse changed the Linnaean epithet to lycopodium. Turner (l.c.) received an alga from the Red Sea that he associated with Stackhouse's illustration, suggesting that the alga illustrated by Stackhouse had come from the Mediterranean rather than from Yarmouth, England, as stated by Stackhouse. Knowing that Fucus lycopodioides had nothing to do with the alga from the Red Sea, Turner cited Fucus lycopodium Stackhouse, but with the exclusion of all synonyms. In accordance with Art. 48.1, Turner is considered to have described a new species whose name is a later homonym. Caulerpa lycopodium is treated as a nomen novum in accordance with Art. 58.3. It is difficult to understand why C. Agardh initially referred Turner's plant to Caulerpa.