"Los quejigares" of Portuguese oaks ("Quercus faginea" subsp "faginea") are the most typical and common of the peninsula, since they are found from the "Serranía de Ronda" in Andalusia to the lower slopes of the Pyrenees. They are much more resistant to the cold and damp than "Q. canariensis"; on the other hand, they need cooler and deeper soils than the Holm oaks with which they come into contact. Although they can grow in any type of soil, in siliceous soils the usually play a secondary part with respect to Holm oaks, cork oaks, and Pyrenean oaks; it is only on chalky soils that it forms forests of any consideration, especially in the northeast quadrant and centre of the Peninsula. The natural area corresponding to the "quejigo" is frequently the black pine ("Pinus nigra" subsp "salzmannii"), which often has been extended at its expense.