Anatomy of Leaf-Margin Lenticels in Eucalyptus denticulata and Three Other Eucalypts

Abstract

The anatomy is described of denticulate leaf margins in Eucalyptus denticulata, E. quadrangulata, E. incrassata and E. laevopinea. The leaves had been collected from trees growing in sites in Victoria or New South Wales. Denticulations are formed by individual secondary meristems, initially associated with primary oil glands. Each meristem produces layers of cells containing phenolic compounds towards the outside of the leaf. The structure of the denticulations is most similar to lenticels. The presence of these leaf-margin lenticels in unrelated taxa such as E. incrassata and E. laevopinea indicates that they have evolved more than once; however, they are a possible synapomorphy uniting E. denticulata and E. quadrangulata as sister taxa. They may function in defence against herbivores.