Silica-scaled Chrysophyceae and Synurophyceae from Madagascar

This paper resumes the first electron microscopy investigation regarding the classes Synurophyceae and Chrysophyceae in Madagascar. 42 taxa (38 new to the country) of the genera Synura, Chrysodidymus, Mallomonas, Chrysosphaerella, Spiniferomonas and Paraphysomonas are illustrated and the morphology of their silica structures examined. Biogeographical problems are discussed, especially emphasizing differences between the 12 regions, here representing the country. While the central plateau has a largely cosmopolitan species composition, the coastal and lowland floras have many tropical components. The SW coast and the island Nosy Be are both species poor.