Leaf Morphology Along Environmental Gradients in Hawaiian Metrosideros Polymorpha

We determined patterns of variation in leaf morphology along independent gradients of elevation, precipitation, and substrate age for the wide-ranging Hawaiian species Metrosideros polymorpha. Leaf mass per unit area, leaf size, and the quantity of leaf pubescence all varied significantly and independently along these gradients. Most importantly, leaf mass per area increased, leaf size decreased, and the amount of pubescence increased with increasing elevation from 70 to 2350 m. Pubescence accounted for up to 35 percent of leaf mass in the high elevation sites.