Abstract: The article presents the results of studying the tissues of the leaf phytoleim of the fossil Taxodium dubium from the Eocene Tavda flora of Western Siberia. Feulgen testing showed the preservation of Feulgen-positive, heterogeneously stained nuclear structures and small granular chromocenters in the cells. The nuclei were red–violet-stained and chromocenters were stained more intensely. This indicates the occurrence of aldehyde groups of deoxyribose in the nuclear chromatin and demonstrates the specific presence of DNA. Additional staining of the preparations with alcian blue and Ehrlich’s hematoxylin displays cell walls and the adjacent intracellular material.