Rustyback Fern (Asplenium ceterach) on a stone wall in Spain. An evergreen fern with lobed leaves that form dense rosettes. The underside of the leaves is covered with scales. Adapted to drought (leaves curl up) thanks to an aptitude for anhydrobiosis and revivification, it is a common plant of rock crevices (chasmophyte plant) and old limestone walls (lithophyte plant).