Polypodium vulgare (Polypody) by BioDivLibrary on Flickr.
"An evergreen, perennial, rhizomatous fern of well-drained, predominantly acidic substrates, including dry-stone walls, roadside banks and rock outcrops. It also occurs as an epiphyte on Quercus and other deciduous trees, mainly in W. Britain and Ireland, and is also found in conifer plantations.” Source

Polypodium vulgare (Polypody) by BioDivLibrary on Flickr.

"An evergreen, perennial, rhizomatous fern of well-drained, predominantly acidic substrates, including dry-stone walls, roadside banks and rock outcrops. It also occurs as an epiphyte on Quercus and other deciduous trees, mainly in W. Britain and Ireland, and is also found in conifer plantations.” Source