Mullein leaf hairs. Coloured scanning electron micrograph (SEM) of hairs (trichomes) on the leaf of a mullein (Verbascum thapsus). Smaller gland hairs (round-tipped, brown) are also seen on the leaf's surface. The large leaf hairs form a woolly layer which protects the plant from pests such as insects and fungi. They also help to reduce evaporation from the plant. Stomata (three at bottom left) can be seen on the leaf's surface. These are small holes which open or close to regulate gas exchange between the leaf's interior and the atmosphere. Magnification: x260 at 6x7cm size. x400 at 4x5"~PORTRAIT"