In the central part of Krasnodar, 13 localities with three petrophytic fern species included in the Red Data Book of Krasnodar Krai have been recorded: Asplenium adiantum-nigrum L., A. ceterach L. (Category 3 – Vulnerable), and Thelypteris palustris Schott (Category 1 – Critically Endangered). All species are confined to old brickwork, primarily in pre-revolutionary and pre-war buildings, which successfully substitute for natural rocky habitats in the urban environment and may serve as refugia for rare petrophytic species. The populations are stable in size; sporulation was observed in A. adiantum-nigrum and A. ceterach. The degree of naturalization of the studied species corresponds to Block II (nos. 5–6) of the Krylov & Reshetnikova naturalization scale, indicating that the species have established themselves in anthropogenic habitats but do not show active spread.

Rudenko I.V.