Abstract
The present contribution is based on collections from five lakes, e. g. L. Manindjau, L. Singkarak, L. Dibaruh, L. Diatas, L. Talang and their outflows and inflows in Central Sumatra, from November 24 to December 9,1984. Concerning L. Talang and L. Manindjau, additional samples were obtained by R. Usman on September,1985.
About 160 taxa from 26 genera are recorded. The following three taxa are described as new variety: Epithemia turgida var. sumatraense nov. var., Gomphonema vibrio var. maior nov. var. and Navicula adnata var. rostrata nov. var. Microphotographs of 164 taxa from the materials are given in 17 plates.
