Aspects of floral morphology in Ambrosina and Arisarum (Araceae)

Abstract

The floral morphology of Ambrosina and Arisarum is analysed from a developmental and phylogenetic point of view. In Arisarum, there are atypical organs displaying male and female characteristics. This developmental study shows that the male flowers of Ambrosina are di- or tri-androus. A close phylogenetic relationship between Ambrosina and Arisarum is supported by their morphology. Both genera have the same type of pollen (ellipsoid, inaperturate, striate–reticulate) and the mode of dehiscence (by a longitudinal slit) of the thecae. In Arisarum, the pollen is mixed with extracellular prismatic crystals of calcium oxalate.Key words: atypical flowers, calcium oxalate crystals, flower development, phylogeny.