For an article on the anatomical structure see eponychium.

In botany the cuticle is the waxy covering produced by the epidermal cells of leaves to protect the plant from excessive water loss. The cuticle is thicker in plants living in dry climates than in those from wet climates, and tends to be thicker on the top of the leaf.

The cuticle is mostly composed of cutin and waxes. "The waxy sheet of cuticle also function in defense, forming a physical barrier that resists penetration by virus particles, baterial cells, and the spores or growing filaments of fungi". (Freeman, 2002). Cutin, as a structural component of the cuticle, is covered with cuticular and epicuticular waxes, a mixture of hydrophobic materials containing C26 to C36 aliphatic compounds.

Cuticle is also used as a term for the exoskeleton, outside of epidermis of many invertebrates.

Source

• Freeman, Scott. Biological Science: Prentice-Hall, Inc: New Jersey. pp710