Foliar secretory structures in Melia azedarach (Meliaceae), a widely cultivated and often invasive tree

ABSTRACTMelia azedarach (chinaberry; syringa), a tree with bipinnately compound leaves, is one of the most widely cultivated of all tropical trees, but has become naturalised in several parts of the world. New observations are presented on the morphology and anatomy of extrafloral nectaries (EFNs). These should serve as baseline information in ecological studies on the invasiveness of the species, as well as its potential biocontrol. We report, for the first time, extrafloral nectaries (EFNs) on the leaflet lamina, as well as capitate glands on very young leaflets. A sugar analysis of the exudate of the former confirmed it to be nectar. In addition, known EFNs occurring in paired recesses at the petiole base were studied anatomically and developmentally. These so-called paired glands were found to be groups of individual and separate EFNs, for which the new term ‘compound EFN’ is suggested. Each EFN making up a compound EFN is similar in structure to the laminar EFNs except that they tend to protrude beyo...