Rustyback Fern

The rustyback fern is a compact evergreen fern of the spleenwort family Aspleniaceae native to western and central Europe, North Africa, and Asia from Turkey through the Himalayas to Tibet. Its intricately divided fronds, up to twenty centimeters long, are covered on their undersides with a dense layer of pale reddish-brown scales that give the species its common name. During summer drought its fronds curl inward, exposing only the scaly underside, an adaptation that lets it grow in fissures of limestone rock and on the mortar of stone and brick walls with little need for humidity, up to elevations of 2,700 meters.