Scanning electron microscopy of the leaf epidermis in Arundinarieae (Poaceae: Bambusoideae): evolutionary implications of selected micromorphological features

Abstract

Arundinarieae (temperate woody bamboos) is a taxonomically challenging group and the taxa in this tribe show a low level of DNA sequence variation, especially for plastid markers. As a result of the scarcity of flowering collections, species identification mainly depends on vegetative features, and leaf epidermal micromorphology has proven to be useful in bamboo taxonomy. In this study, we used scanning electron microscopy to investigate the abaxial leaf epidermal micromorphology of 94 species in 24 genera of Arundinarieae and three species of Bambuseae. Leaf epidermal characteristics differed mainly in the number and distribution pattern of papillae. Seven papilla forms were assigned, which had little taxonomic value at the generic and subtribal levels. However, the papilla patterns combined with other leaf epidermal features were useful in the discrimination of several species. Most papilla types were shared between tribes Arundinarieae and Bambuseae. We assessed the phylogenetic implications of the leaf epidermal micromorphology based on recently published molecular phylogenetic analyses. With one exception, none of the papilla types corresponded to a particular clade in the plastid or nuclear phylogenetic trees. Based on these results, the papilla patterns have limited phylogenetic value. (C) 2014 The Linnean Society of London