Phytoplankton of the lake Baikal during late summer

Systematic list of plankton algae and their quantitative characteristics for August-September 1981-1998 studied during circum-baikalian expeditions samples processing are presented. The list of plankton algae is completed with the new species for lake. Additionally the composition of phytoplankton during the same months in 2003-2004 was studied. Diagnosis for some species of divisions Cyanophyta and Chrysophyta do not correspond to existing ones. Original morphological characteristics for these species are described, photos are presented. Taxon from genus Spirulina described as new at the level of variation.