Distribution of Cystopteris fragilis (L.) Bernh. in the Inder salt-dome region and adjacent territories of the northern Caspian

The article presents information on the distribution of the fern Cystopteris fragilis (L.) Bernh. in the Inder salt-dome region and adjacent territories of the Caspian lowland. The ecological features of C. fragilis in its characteristic habitats, represented by well-like karst sinkholes, are provided. It is suggested that C. fragilis in the Caspian lowland is a relic from the Tertiary period, with a disjunctive range, preserved during the Khvalynian transgression on the salt-dome uplands-refugia of Bish-choho, Inder, and Bolshoye Bogdo.