Abstract Marked Potamogeton leaves of known age were examined by scanning electron microscopy. Leaves showed a distinct succession of microflora. Prosthecate bacteria developed after 6 weeks of leaf growth and were associated with cuticular erosion and epidermal pitting. Senescent leaves (14 weeks old) showed extensive cuticular peeling and epidermal cell wall rupture, and it is suggested that the pitting noted at 6 weeks is the precursor of such damage. This could well prepare the leaf for rapid leaching to take place immediately after death.