The Epiphyllous Algal Colonization of Elodea Canadensis Michx.: Community Structure and Development

Summary The initiation and development of the epiphyllous algal community on the aquatic macrophyte Elodea canadensis Michx. were described using light and scanning electron microscopy (SEM). From initial discrete colonizing cells, a confluent matrix developed which included bacteria, algae, fungi, protozoa, mucilage and inorganic particles. The microtopography of the leaf surface affected'the initial colonization and influenced the growth of certain species. The tips, bases and edges of the leaves were the first areas to become colonized. As the age of the leaves increased, the density of the epiphyllon increased and the structure of the community changed. On young leaves, the Chlorophyta represented 80% of the community standing crop whilst on pre‐senescent leaves this proportion was reduced to 52%. The Bacillariophyta increased in proportional representation from 17% on young leaves to 47% on the older leaves.