<p> Previous work on the ultrastructure of leaf surfaces has been confined to commercial terrestrial plants. Until recently there was a conflicting overlap of definitions of surface structures. Lately, studies have concentrated on the role of the epicuticular wax layer in surface phenomena such as water permeability, transpiration, and herbicide susceptibility. The initiating factors in surface wax formation and the mode of extrusion still remain unresolved. </p> <p> An emergent hydrophyte, Zizania aquatica L., was selected to attempt to clarify the initiation and extrusion of epicuticular wax. The first appearance of epicuticular wax occurs while the whole plant is submerged. The wax platelet shape is probably controlled by an endogenous circadian rhythm with very little environmental control. The significance of water depth, temperature, continous light, physical and chemical abrasion are discussed in terms of the surface morphology of the three types of leaves. </p> / Thesis / Master of Science (MSc)