The significance of the leaf epidermis in the taxonomy of the Combretaceae.

The value of the leaf epidermis, particularly of the glandular trichomes, in the identification and classification of Combretum subgenus Combretum in the African continent is assessed. The peltate hairs ('scales'), found in every species of this subgenus, show a wide range of anatomy and have proved extremely valuable in assessing taxonomic relationshipS. In general, differentiation by these means is at the sectional level, and the species are treated under the 22 sections now recognized in Africa. It may be concluded that the systematic value of the scales is at least as great as that of any other organ in the subgenus, and in a great number of cases valuable indications have been obtained for the first time. In an appendix three new sections are described.