Hypnea esperi.—Grunow, 1867: 79.— G. Martens, 1868: 92–93.— Reichardt, 1871: 25.— Hemsley, 1884: 281.— Børgesen, 1950b: 16.— Varma, 1959: 249.— V. Krishnamurthy & H. Joshi, 1970: 22.— Isaac, 1971: 18.— Hackett, 1977: 19.— Knutzen & Jaasund, 1979: 3.— Teo & Wee, 1983: 96, 98, fig. 100.— Untawale, Dhargalkar, & Agadi, 1983: [31].— P. Subba Rao et al., 1985: 33.— Phang & Wee, 1991: 59 (with query).— Kalugina-Gutnik, Perestenko, & Titlyanova, 1992: 18 (table 1).— Subba Rao et al., 1992: 182.— Titlyanova, Perestenko, & Kalugina-Gutnik, 1992: 43.— Zvyagintsev & Ivin, 1992: tables 3, 4.— Mshigeni & D. Chapman, 1994: 254.
Intended nomenclatural synonym:
* Hypnea musciformis (Wulfen) Lamouroux var. esperi J. Agardh, 1851 [1851–1863]: 442–443, nom. illeg. (type locality: Mauritius).—De Toni, 1900: 472–473.— Hariot, 1902: 471.
Intended taxonomic synonyms:
* Hypnea musciformis (Wulfen) Lamouroux var. flexuosa Harvey, 1834a: 154 (type locality: Mauritius).
* Hypnea musciformis (Wulfen) Lamouroux var. muscoides Harvey, 1834a: 154 (type locality: Mauritius).
* Hypnea musciformis (Wulfen) Lamouroux var. nigra Harvey, 1834a: 154 (type locality: Mauritius).
INDIAN OCEAN DISTRIBUTION: Aldabra Islands, India, Kenya, Laccadive Islands, Madagascar, Maldives, Mauritius, St. Paul Island, Seychelles, Singapore.
Note: Bory de Saint-Vincent (1828 [1826–1829]: 157–158), believing that a collection made by Dumont d'Urville at Concepción, Chile matched the protologue of Fucus nootkanus Esper (1802 [1802–1808]: 30, pl. CXXV; type locality: Nootka Sound, Vancouver Island, Canada), transferred Esper's species to Hypnea but unnecessarily changed the epithet to esperi [`esperii']. Hypnea esperi is thus an illegitimate name to be retained in the synonymy of F. nootkanus. The identity of F. nootkanus is uncertain. J. Agardh (1851 [1851–1863]: 451) thought that it might be conspecific with his new species, Hypnea nidifica J. Agardh (l.c.; type locality: Hawaiian Islands). Doty (1947b: 164) thought that it was conspecific with Pikea californica Harvey (1853: 246–247), while P. Silva (1953: 225–226) thought that it was conspecific with Bonnemaisonia californica Buffham (1896: 181–182, pl. IX: figs. 8–10). Examination of an isotype specimen (in BM) by Silva (unpublished) has revealed an associated biota indicative of tropical or subtropical waters, thus eliminating Nootka Sound as the provenance and supporting J. Agardh's opinion.A valid, albeit illegitimate name was given to this entity at varietal level by J. Agardh (op.cit.: 442–443), who described a cluster of collections as Hypnea musciformis (Wulfen) Lamouroux var. esperi. While including the Dumont d'Urville collection from Chile, he explicitly excluded F. nootkanus. The name is nomenclaturally superfluous, however, since the protologue included three varieties of H. musciformis described from Mauritius by Harvey (1834a: 154). If the entity currently passing under the name H. esperi is recognized at the level of species, it must receive a different name.