Abstract
The common saprophilous and saproxenous species groups in the flowing and standing waters were obtained based on mathematical principle. The number of taxa belonging to the former is 29, and that to latter is 58.
DAIpo 50 mark is a common boundary which distinguishe d between oligosaprobic and mesosaprobic zone in the flowing and standing waters.
Occurring of such a diatom assemblages as saproph ilous taxon becomes dominant species, is limited in the water quality zone with below 50 in DAIpo marks, and that of saproxenous species becomes dominants, is limited in where with over 50in DAIpo marks, in both flowing and standing waters.
Saprophilous and saproxenous species do not usually coexist with each other as dominant or subdominant species.
Shannon's diversity index vary describing a parabola with increase of pollution degree. And the variational pattern of the index shows a symmetry between the right and left halves separated by the boundary of which DAIpo marks is 50.
