Pericarp structure and generic affinities in the Anacardiaceae

Pericarp structure is surveyed in 29 genera. Homologous regions termed exocarp, mesocarp and endocarp are established. While exocarp and mesocarp structure show some uniformity, there are two very distinct types of endocarp, designated the Anacardium-type and the Spondias-type. The distribution of these indicates that the current division of the family into five tribes is artificial. The occurrence of the Spondias-type in Canarium, a member of the sister group Burseraceae, suggests that this type is plesiomorphic in the Anacardiaceae. In addition, the presence of the Anacardium-type in Blepharocarya (Blepharocaryaceae) and Orthopterygium Qulianiaceae) further supports the inclusion of these taxa in the Anacardiaceae.