The Coscoja usually appears as a dense, ramous and thorny shrub, up to 2 meters high, although sometimes it can reach arboreal bearing, then reaching 10 or 12 meters. The bark is ash grey and smooth, although it cracks with age. The leaves are usually 1.5-5 cm long and 1-2 cm wide; they are simple, persistent, oval or elliptical and prickly, with spiny teeth on the margin. They are smooth and hairless on both sides, character that is well observed in adult leaves. This property, together with the green color, not as dark as that of the holm oak, is what differentiates them, because they can be confused mainly when they form stocky stands, since their ecology sometimes coincides. The male flowers of the Coscoja grow in long hanging ochre bouquets, called catkins, which appear during the spring. The acorn is bitter and its cap or husk has prickly, protruding scales, especially the upper ones. It is a substrate-indifferent species that grows best on basic soils, tolerating even chalky soils. It breeds in dry and stony soils, withstands prolonged droughts where it displaces the oak formations, does not stand frost well and is a species adapted to fire. The thick undergrowth of kermes oak often forms a dense, spiky tangle that resprouts vigorously after fires. Its ecological importance is exceptional, as it is a refuge for numerous species of fauna and is protective and soil-forming. It is distributed from sea level up to 1000-1200 m, where it acquires a creeping habit. It forms pure masses or lives mainly with holm oaks, junipers, wild olive trees, palm trees and carob trees. Coscoja is distributed naturally throughout the Mediterranean region, becoming more common to the west. In the Peninsula is more abundant in the south and east.