An active or dormant bud or cluster of buds is usually located in the axil. The leaf blade is composed of several layers. On the top and bottom is a layer of thickened, tough cells called the epidermis. The primary function of the epidermis is protection of leaf tissue. The way in which the cells in the epidermis are arranged determines the texture of the leaf surface.
Some leaves have hairs that are an extension of certain cells of the epidermis.
The African violet has so many hairs that the leaf feels like velvet. Part of the epidermis is the cuticle, which is composed of a waxy substance called cutin that protects the leaf from dehydration and prevents penetration of some diseases. The amount of cutin is a direct response to sunlight, increasing with increasing light intensity. For this reason, plants grown in the shade should be moved into full sunlight gradually, over a period of a few weeks, to allow the cutin layer to increase and to protect the leaves from the shock of rapid water loss or sun scald. The waxy cutin also repels water and can shed pesticides if spreader-sticker agents or soaps are not used.