ANATOMY OF LEAF-MARGIN LENTICELS IN EUCALYPTUS-DENTICULATA AND 3 OTHER EUCALYPTS

Anatomy of denticulate leaf margins in Eucalyptus denticulata I.O. Coo k & P.Y. Ladiges, E. quadrangulata Deane & Maiden, E. incrassata Labil l. and E. laevopinea R.T. Baker is described. Denticulations are forme d by individual secondary meristems, initially associated with primary oil glands. Each meristem produces layers of cells containing phenoli c compounds towards the outside of the leaf. The structure of the dent iculations is most similar to lenticels. The presence of these leaf-ma rgin lenticels in unrelated taxa such as E. incrassata and E. laevopin ea 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.