The Physiological Significance of the Peculiar Morphology of the Pitcher-Like Leaves of Sarracenia Purpurea L.

Abstract

The physiological interaction of the pitcher-leaves of Sarracenia purpurea L. with its immediate environment is described quantitatively, in terms of radiant and detrital energy fluxes. The insectivorous nature of the plant as a functional explanation of the leaf morphology is de-emphasized. The growth of pitcher leaves under sufficient light and constant temperature is not enhanced by the presence of detritus in the pitcher-pool. The thermal buffering capacity of the water enclosed by the pitcher-leaves allows for maximum photosynthetic surface area. The pool water may also act as a reservoir for carbon dioxide for leaf photosynthesis. The water level of the pitcher in the mature leaf is probably maintained by osmotic flow through the roots from the bog medium.