The Ecological Significance of Lobed and Toothed Leaves in Temperate Forest Trees

Leaves with toothed and lobed margins are frequent in deciduous forests but are rare in moist tropical forests. We hypothesize that leaf teeth may be important to deciduous species as sites of precocious, early season photosynthesis. To test this hypothesis we dosed leaves with 14CO2 and used autoradiography to examine the spatial distribution of photosynthesis within immature leaves of 18 woody species of North Carolina Piedmont forests. We found a significant concentration of early season photosynthesis on the margins of eight species with prominent teeth or lobes, but not in seven toothed or lobed leaf species and in none of the four entire-leaf species.