Comparative foliar epidermal morphology of the West African species of the genus Afzelia smith (Leguminosae: Caesalpinioideae)

Abstract

The epidermal features of the leaves of the six West African species of Afzelia were examined and compared using light and scanning electron microscopy. The leaves are hypostomatic in all species and stomatal type is paracytic. Anticlinal walls may be undulate or straight-curved and stomatal index ranges from 17.48% in A. bella var. gracilior to 25.20% in A. bipindensis. Porrect and flattened scales distinguish the infra-specific taxa of A. bella while presence of unicellular trichomes separates A. pachyloba from other species. The leaf surface is entirely covered by epicuticular wax deposits and the stomata are either raised or sunken in the genus. Using these foliar epidermal characters, an artificial key has been prepared to facilitate identification of the species.