A contribution to the leaf and young stem anatomy of the Combretaceae

Abstract

A comprehensive survey of anatomical features of the leaf and young stem in southern African Combretaceae has been conducted. Anatomical descriptions of the native genera (Combretum, Lumnitzera, Meiostemon, Pteleopsis, Quisqualis and Terminalia) are provided. Attention was paid to the description of the observed structural diversity, as well as to an assessment of its possible systematic significance. Unusual anatomical features are present in the leaves of a number of species; these include various glands, complex vascular tissue and arm-palisade cells. Interpretation of the vascular tissue comprising the midrib of the leaves is particularly problematic; there is considerable interspecific variation, notably in pattern of vascular tissue arrangement and the degree of external and internal phloem development. The anatomy of the mangrove Lumnitzera racemosa, a highly-specialized member of the family, is peculiar and an attempt is made to link certain features with possible function. Some of the structural characters are of systematic significance and useful for generic and sectional recognition as well as the identification of sterile material. Combretum section Angustimarginata can be distinguished by a combination of leaf blade anatomical features and Terminalia section Psidioides by the tanniniferous palisade cells in the leaf blade. © 2002 The Linnean Society of London.