Inflorescence morphology of some South American Anacardiaceae and the possible phylogenetic trends.
The inflorescences of 15 native and one introduced species belonging to the genera Anacardium, Loxopterygium, Mangifera, Mauria, Mosquitoxylon, Schinus, Spondias, Tapirira and Toxicodendron are described. The tribal divisions in the Anacardiaceae are supported by the inflorescence morphology. Tribe Spondiadeae has paniculate inflorescences whereas tribe Anacardieae and tribe Rhoeae both have thyrsoids. Toxicodendron is exceptional for the tribe Rhoeae having axillary panicles. Thyrsoids are hypothesized to be derived from panicles by a 2-step process including neoteny and enriching by cymose branching.