The following taxon apparently lies within the circumscription of Synarthrophyton patena but has not yet been transferred or reduced to synonymy:
Lithophyllum capense Rosanoff, 1866: 86–88, pl. VI: figs. 13, 15 (type locality: Cape Agulhas, South Africa fide isotype in UC).—Woelkerling & Verheij, 1995: 38.
Lithothamnion capense (Rosanoff) Foslie, 1898b: 7.—Foslie, 1900e: 14.— Heydrich, 1901: 544.— Foslie, 1907b: 15.— Foslie, 1929: 39, pl. X: fig. 2.— Adey & Lebednik, 1967: 68.
Lithothamnion patena (J. Hooker & Harvey) Heydrich forma capense (Rosanoff) Heydrich, 1907: 223, footnote.
INDIAN OCEAN DISTRIBUTION: South Africa.
Note: Hohenacker (1855 [1852–1862]: no. 236) used the name Melobesia capensis without a description and attributed it to Lamouroux, but according to Rosanoff (l.c.), who was the first to provide a description for the species, this alga in Lamouroux's herbarium bears the manuscript name Millepora fucorum.