Olive leaf trichomes. Coloured scanning electron micrograph (SEM) of the scale-like leaf hairs (trichomes) on an olive tree leaf (Olea europaea). These leaf hairs prevent evaporative water loss during dry conditions or high winds. They help the olive tree to survive in the hot and seasonally dry climates in which it lives. Gas content in the leaf is regulated by the stomata (pores). Magnification: x350 when printed at 10 centimetres wide.