The outer layer of leaves and stems of plants is called epidermis. The exterior of the root is called epibeoma. Skin is formed from the protoderm or dermatogen of the dividing tissue at the root and stem apex. Cutin and suberin accumulate in the epidermis to form a thick layer of cuticle. The leaves of plants like sugarcane, rice, bamboo, grass, reeds etc. have silica cells and cork cells, so the edges are sharp. Leaves of plants like banyan, saffron, fig, rubber etc. contain large cells called lithocysts and contain calcium carbonate called cystoliths. Myrosine cells are present in the leaves of mustard family plants (mustard, rye, radish). It secretes myrosin enzyme. Plants like wheat, wheat, sugarcane etc. have large cells called bulliforms in their leaves. Bulliform stores water. Flower petals and fruit skin contain pigments called anthocyanins. Outside the cell wall there is a thin coating of cutin, suberin, lignin, wax etc. The root cuticle is called the pilosebaceous layer because the root hairs arise from the root cuticle. The skin of bots, ostriches, rubbers, crabs, corbi and orchids is multi-layered.