Witch-hazel leaf surface. Coloured scanning electron micrograph (SEM) of the upper surface of a witch-hazel (Hamamelis virginiana) leaf. A branching hair cell or trichome is seen at lower right. Trichomes may function in reducing water loss or in defending the plant against insects. The blade of the leaf comprises a layer of epidermal cells (green), which protect the leaf and secrete a waxy cuticle. Two stomata (leaf pores) are seen at top left and upper right. These are the sites of gaseous exchange. Witch- hazel is used in herbal medicine to treat sprains, burns and skin inflammation. Magnification: x130 when printed 10 centimetres wide.