Caulerpa geminata Harvey, 1855b: 564 (type locality: Rottnest Island, Western Australia).—Womersley, 1984: 268–269.— Huisman & Walker, 1990: 365.
Caulerpa sedoides C. Agardh var. geminata (Harvey) Harvey, 1859a: pl. LXXII: figs. 3, 4.—J. Agardh, 1873: 39.— De Toni, 1889: 480.
Caulerpa sedoides C. Agardh forma geminata (Harvey) Weber-van Bosse, 1898: 387–388.—Weber-van Bosse, 1913a: 114.
INDIAN OCEAN DISTRIBUTION: Australia, Indonesia (Semau).
Note: According to Womersley (1956: 370), Caulerpa sedoides forma crassicaulis and forma geminata "appear to be only growth or ecological forms, the arrangements and size of the ramenta being very variable, even on one plant''.