Asplenium trichomanes

Usually found on stone walls and cliff faces, often in wet conditions. "[M]aiden-hair spleenwort has two subspecies that are nearly identical in appearance. Asplenium trichomanes ssp. trichomanes, a diploid, grows on acidic rocks while Asplenium trichomanes ssp. quadrivans, a tetraploid, grows on calcareous rocks." (Bruce Gilman, Vasculum, newsletter of the Canandaigua Botanical Society, summer 2025)