Oak leaf hairs. Coloured Scanning Electron Micrograph (SEM) of the underside of a leaf from the Evergreen or Holm oak, Quercus ilex. The leaf is covered with tiny hairs (trichomes) which may reduce water losses or protect it from insects. Q. ilex has leaves throughout the year. In the wild it grows in old stands of forest in the warm climate of the Mediterranean region and southwest Europe. Old forests of Q. ilex are becoming rare because of human activities. Although it is a hardy plant, it cannot tolerate very cold temperatures. Its leathery leaves are grey on their underside and dark green on top. Magnification: x170 at 6x6cm size.