XVI International Botanical Congess

Leaf and stem anatomy is increasingly important in systematic studies. In the family Labiatae, surface characters like trichomes, glands and stomata have been particularly useful in revealing affinities. The purpose of this study was to show the significance of these characters in delimiting the problematic genus, Plectranthus. The SEMs showed an array of differences in the sizes and shapes of the trichomes, glands and stomata and also the surface ramifications. These were used to identify and separate the species.