A new alien species Scirpus cyperinus (Cyperaceae) to the flora of the Smolensk Region

An alien North American species, Scirpus cyperinus (L.) Kunth (Cyperaceae), earlier known in Russia only in the Kostroma Region, was found in the Smolensk Region. Characteristics of the locality of the species are given and plant communities with its participation are described. The monodominant phytocoenoses formed by this species are combined into the new ass. Junco effusi–Scirpetum cyperini ass. nov. The new locality of abundant occurrence of the species is removed from its primary range and known locations in Eastern Europe.