4th Annual WML Academic Symposium

Planchonella sandwicensis is a Hawaiian endemic tree distributed in mesic to dry forests on all main Hawaiian Islands. Previous studies of this highly variable species have suggested an east-west variation in leaf morphology. Our previous research showed that specific leaf area and stomatal density exhibited a significant positive correlation with rainfall. This encouraged us to conduct further studies to see if similar findings would be evident in the internal leaf anatomy. Collections of this plant were made from Kaua`i, O`ahu, Moloka`i, Maui and Hawai`i in 2012. Leaves were fixed and sectioned to 20 μm with a cryostat microtome. Leaf sections were photographed and attributes of the leaf were quantified. We investigated geographical and ecological correlates to features of internal leaf anatomy in the species. Some components of the leaf anatomy were significantly correlated to elevation and rainfall; however, there does not seem to be a clear pattern with these correlations. Some islands possessed some unique leaf attributes. Many of the leaves exhibited multiple lower and upper epidermis layers. This may be evident of the tree’s desiccation avoidance mechanism. Specimens from O`ahu possessed smaller ranges of variation in multiple epidermis thickness than other islands. There did not appear to be a geographic pattern in leaf anatomy variation.