ONTOGENY OF THE FRUITS OF TWO ANOMALOUS AFRICAN WOODY GENERA, POLEMANNIOPSIS AND STEGANOTAENIA (APIACEAE), AND THEIR PHYLOGENETIC RELATIONSHIP

Abstract

The fruits of two anomalous African woody Apiaceae, Polemanniopsis marlothii and Steganotaenia araliacea, differ in structure when mature though the ovaries are very similar, both being heteromorphic in young flower stage. This unexpected heteromorphism in S. araliacea has important implications for future studies of basal genera and the interpretation of fruit characters in general. Both taxa also have unique ‘intrajugal cavities’ in the ovaries and fruits, which supports the idea that the two genera are closely related, sharing some characters with the Hydrocotyloideae and Saniculoideae. This provides morphological and anatomical evidence to support the previous hypotheses on their relationship with Saniculoideae. Their basal position is also supported by characters shared with other basal genera previously included in Hydrocotyloideae, such as the lateral wings and slightly lignified endocarp in Polemanniopsis and Steganotaenia.