The cuticle is a protective layer covering the epidermal cells on some plants. It is composed mainly of cutin, and it is non-living. The cuticle layer prevents the plant from losing water and protects it from organisms that could harm the plant. It also supports the plant and prevents damage from UV rays. The cuticle layer has a function similar to that of human skin. In the picture above, the cuticle layer is the glossy coating covering the leaf.