Floristic regional subdivision and syntaxonomy

The advantages of using floristic subdivision of the area for syntaxonomic purposes are discussed. The analysis of changes in floristic composition of East-European broad-leaved forest communities along the West-East continentality gradient shows that floristic differences between the adjacent provinces correspond to changes in species composition at the association or the alliance level. A new association, Lathyro nigri—Quercetum roburis (all. Aceri tatarici—Quercion Zolyomi 1957, order Quercetalia pubescenti-petraeae Klika 1933), is established for the Southern Non-Chernozem region of European Russia.