Anatomical studies in West Malaysian Icacinaceae

Abstract

On the basis of a comparative anatomical study of the leaf lamina and petiole of six genera of Icacinaceae in West Malaysia, these genera can be classified into four closely knit groups by virtue of their many shared characters: Group I comprises Cantleya, Gomphandra and Stemonurus whereas Groups II and III are made up of Gonocaryum and Sarcostigma, respectively. The climber genus Iodes is classified into Group IV. Taxonomically useful characters include the shape of the vascular bundles in both the midrib and petiole, the presence of funnel-shaped palisade cells, foliar sclereids, tannin crystals, hypodermis layer and accessory or wing bundles in the petiole. A key to the genera and the descriptions of each species and variety based on anatomy are given. Phylogenetic relationship among the genera are also discussed based on the study with data supplemented from other taxonomic sources.