The following two taxa, which apparently lie within the circumscription of Sargassum capillare, have not been cited subsequent to their proposal:
Sargassum tenue J. Agardh var.? fuscescens Grunow, 1915 [1915–1916]: 373 (type locality: Sunda Strait, Indonesia).
INDIAN OCEAN DISTRIBUTION: Indonesia (Sunda Strait).