The following taxon apparently lies within the circumscription of Sporolithon schmidtii but has not yet been transferred or reduced to synonymy:
Archaeolithothamnion schmidtii Foslie forma dissitum Foslie, 1903b: 464, pl. XXIV: fig. 1 (`dissita') (type locality: Addu Atoll, Maldives).—Adey & Lebednik, 1967: 85 (without designation of forma).— Hackett, 1977: 14.— Woelkerling, 1993: 78.
INDIAN OCEAN DISTRIBUTION: Maldives.
Note: In describing Archaeolithothamnion schmidtii forma dissitum, Foslie mentioned only two specimens, one known with certainty from Addu Atoll, the other known with uncertainty from Hulule, Male Atoll. One of these specimens is reproduced photographically as Pl. XXIV: fig. 1, but the legend does not cite its provenance. Under A. schmidtii in Foslie's herbarium at TRH, however, Adey & Lebednik (1967: 85) found the Hulule specimen (including slide 749) and one from South Nilandu (including slide 767), but nothing from Addu Atoll. Woelkerling (1993: 78) indicated that the photographed specimen is from South Nilandu and designated it as lectotype. It seems that a label mix-up is involved.