Until recently the distribution of fern Cladophlebis kanskiensis Kost. was limited by Middle Jurassic sediments of the Kansk Basin (Kamalinskaya Formation). In the study of the plant remnants from key section of Prisayanskaya Formation the authors found the impressions of fronds and pinnae of Cl. kanskiensis Kost. A distinguishing featurenof this species is a peculiar structure of the pinule bases: the upper edge of the base is dilated (as if runs up) and the lower one is slightly contracted and forms s shallow rounded sinus. The studied samples are the first finding of this species in the Irkutsk Basin. Distribution of this species within the Kansk and Irkutsk Basins presupposes the existence of floristic links between them in the Middle Jurassic. Among pinnulate ferns of the Irkutsk Basin the most akin species are Cl. angarensis Pryn. и Cl. irkutensis Pryn.