Cuticle is considered to be any covering layer or membrane; cuticle can be on animals or plants. In animals, cuticle is a solid formation on the surface of epithelial tissue cells. It functions protectively and supportively. Cuticle is composed of chitin to provide strength and of lipids to repel water. In plants, cuticle is a thin film that covers the epidermis of the leaves and stem of the plant. Cuticle is composed of cutin. Its functions include protection, provides strength, repels water, limits transpiration, and reflects some sunlight. In the picture above, the shiny part on the leaf is the cuticle.