Fucus divaricatus R. Brown ex Turner, 1809–1811: 110–111, pl. 181, nom. illeg. (type locality: Australia).
Sphaerococcus divaricatus C. Agardh, 1817: XVII.
Hypnea divaricata (C. Agardh) Greville, 1830: lix.—J. Agardh, 1851 [1851–1863]: 448–449.— Grunow, 1867: 79–80.— Kützing, 1868: 9, pl. 25: figs. d–g.— G. Martens, 1868: 30, 92–93.— G. Martens, 1871b: 468.— Theobald, 1883: 29.— Askenasy, 1888: 46.— De Wildeman, 1897a: 171.— De Toni, 1900: 478.— De Wildeman, 1900: 409–410.— Reinbold, 1907: 570.— Weber-van Bosse, 1913b: 117.— Weber-van Bosse, 1914: 281.— De Toni, 1924: 279–280.— Jadin, 1935: 166.— Zaneveld, 1956: 42.— Zaneveld, 1959: 121.— K. Srinivasan, 1961a: 229.— V. Krishnamurthy & H. Joshi, 1970: 22.— Untawale, Dhargalkar, & Agadi, 1983: [31].
Hypnea musciformis (Wulfen) Lamouroux var. divaricata (C. Agardh) Harvey, 1834a: 153.
INDIAN OCEAN DISTRIBUTION: Aldabra Islands, Andaman Islands, Australia, Burma, Indonesia (Java; Sumatra; Timor), Mauritius, Nicobar Islands.
Note: Fucus divaricatus Brown ex Turner, the intended basionym of Hypnea divaricata, is not priorable since it is a later homonym of F. divaricatus Linnaeus (1753: 1159; syntype localities: England and Portugal), which Turner (1802a: 117) placed in the synonymy of F. vesiculosus Linnaeus (1753: 1158; type locality: Atlantic Ocean). Sphaerococcus divaricatus C. Agardh is treated as a nomen novum in accordance with Art. 58.3. According to Womersley (1994: 443), F. divaricatus R. Brown ex Turner is probably conspecific with H. charoides Lamouroux.