Sizes and Shapes of Liane Leaves

We have developed evolutionary models to account for ecological patterns in the size and shape of vine leaves. Leaf size is predicted via an economical model in which photosynthetic gains due to enhanced gas exchange are balanced with the metabolic losses incurred in replacing the concomitant water loss. Mechanical efficiency and appropriate orientation in a light field form the basis of our model for leaf shape. Data from montane rain forest in Venezuela and from varied habitats in Costa Rica illustrate the predicted trends along vertical and horizontal microclimatic gradients. Large, cordate-based leaves with long petioles are favored in sunny situations, while small, narrow-based leaves with short petioles are favored in more shady environments. Compound or deeply lobed leaves of the smallest effective size are expected in the most exposed positions.