The genus Dictyota (Dictyotaceae, Phaeophyta) from Indonesia in the herbarium Weber-van Bosse, including the description of Dictyota canaliculata spec. nov

In the framework of a revision of the genus Dictyota J.V. Lamour. in the Indian Ocean, all specimens from Indonesia present in the herbarium Weber-van Bosse (L) were re-examined. This resulted in a total of 9 species, one species including two different growth forms. Our identifications differ substantially from those of Weber-van Bosse (1913). Specimens recorded as D. apiculata J. Agardh were re-identified as D. crispata J.V. Lamour., which is the correct name for D. bartayresiana sensu Vickers; similarly was D. bartayresiana var. ß re-identified as D. cervicornis Kütz., D. fasciola (Roth) J.V. Lamour. as D. ceylanica Kütz. and D. ceylanica Kütz. var. rotundata Weber Bosse as D. friabilis Setch. Dictyota pardalis Kütz. considered as a distinct species by Weber-van Bosse (1913: 184), is treated as a synonym of D. cervicornis. In addition a new combination is made for a growth form of the latter, characterized by recurved branchlets: D. cervicornis f. pseudohamata (Cribb) De Clerck & Coppejans. Dictyota beccariana Zanardini is considered to be a synonym of D. ciliolata Sond. ex Kütz. A single specimen, previously assigned to D. beccariana, belongs to D. dumosa Børgesen. This is the first report of D. dumosa for the Malayan region. A new species, D. canaliculata De Clerck & Coppejans is described from preserved material, not reported in Weber-van Bosse (1913).