cutin

A mixture of complex macro-molecules forming the waxy cuticle that covers the aerial parts of most higher Plants. Cutin  contains  long-chain  fatty acids and polyhydroxy derivatives of these fatty acids (e.g. 10,16-dihydroxy-palmitic acid). These molecules are cross-linked through ester bonds in a more or less random fashion to form a large interlinking matrix, relatively impervious to water and gases.