Haliseris dichotoma Suhr, 1840: 259–260, nom. illeg. (type locality: "Cap der guten Hoffnung'' [mouth of Omsamculo (Umzimkulu) River, Natal, South Africa fide Drège, 1843: 156]).—Drège, 1843: 156.— Areschoug, 1847a: 2, pl. III.— J. Agardh, 1848b: 118.— Kützing, 1849: 562.— Areschoug, 1851: 27–28.— Kützing, 1858: 23, pl. 57: fig. I.— Barton, 1893: 110.— De Toni, 1895b: 256–257.— Delf & Michell, 1921: 101.— Stephenson, 1944: 300, 302, 317, 348.— Stephenson, 1947: 298.
Neurocarpus dichotomus Kuntze, 1891: 907.
Dictyopteris dichotoma (Kuntze) O. Schmidt, 1938: 219.—Levring, 1938: 19.— Eyre, Broekhuysen, & Crichton, 1938: 92, 102, 107.— Eyre & Stephenson, 1938: 32.— Stephenson, Stephenson, & Bright, 1938: 8.— Seagrief, 1988: 42, fig. 5:3.
INDIAN OCEAN DISTRIBUTION: South Africa.
Note: Haliseris dichotoma Suhr is not priorable since it is a later homonym of H. dichotoma (Hudson) Sprengel (1827: 328), based on Ulva dichotoma Hudson (Dictyota dichotoma (Hudson) Lamouroux (q.v.)). Neurocarpus dichotomus Kuntze is treated as a nomen novum in accordance with Art. 58.3. The transfer of H. dichotoma Suhr to Dictyopteris was proposed twice in 1938—by O. Schmidt on 25 May and by Levring (1938: 19) on an undetermined day. In the absence of a precise date of publication for Levring's paper, it seems reasonable to accept Schmidt as the combining author.As expressed by Papenfuss in his notes, manuscript, and herbarium, the identity of this species is uncertain. After examining authentic specimens at Stockholm (S) in September 1939 and again in July 1950, Papenfuss concluded that Dictyopteris dichotoma was a synonym of D. macrocarpa (Areschoug) O. Schmidt [p. 583] and that both names applied to the species that he was intending to describe as D. longifolia. Stephenson (1947: 298) recorded "true dichotoma Suhr'' from Cape Infanta while adopting Papenfuss's manuscript name for "the common plant which has long been known as dichotoma''. This treatment is puzzling because Papenfuss (unpublished) does not distinguish between D. dichotoma (Suhr) O. Schmidt and D. dichotoma as used by later authors. In a manuscript prepared by Mitsuo Chihara in 1963 under Papenfuss's direction, D. longifolia is retained while the possibility that D. dichotoma is the sexual phase of D. macrocarpa is considered.