1985 Volume 1 Pages 21-31
The present research pursues to discuss the origin and evolution of freshwater diatoms based on the data obtained by the surveys for the inorganic acid lakes in Japan and alkaline lakes in Africa. From this research, next two ideas were assumed.
1. The families included many acidophilous and acidobiontic taxa appeared at early phase in the process of diatom evolution, whereas these included man y alkaliphilous and alkalibiontic taxa appeared at late phase in both the ce ntric diatoms and the pennate.
2. Freshwater diatoms appared in earlier phase of the Earth's history than the marine.
