Wall Rue, Asplenium ruta-muraria grows alongside the Rusty-back Fern in the crevices of an old wall in Ossett. It is a common fern of walls and limestone crevices.
Leathery leaves and long wiry roots are useful adaptations for conserving water.
Like the Rusty-back it is a member of the Spleenwort family, used as a herbal remedy for diseases of the spleen and also in the treatment of rickets.