Comparative anatomy of leaf petioles in temperate trees and shrubs: the role of plant size, environment and phylogeny.

We conclude that species' temperature and precipitation optima, plant height, and leaf area and thickness exerted a significant control on petiole anatomical and morphological structures not confounded by phylogenetic inertia. Species with different evolutionary histories but similar thermal and hydrological requirements have converged to similar petiole anatomical structures.