R. Vilatersana, J. M. Villodre, A. Susanna
Nov 1, 2001
: Recent molecular and karyologic studies have deeply modified the delimitation of the genera of the Carthamus complex, and have led to a new classification of the group in four genera (Carduncellus, Carthamus, Femeniasia and Phonus). Molecular studies have confirmed the position of the group among the derived genera of the subtribe Centaureinae, and have suggested a faint relationship between the Carthamus complex and the small genus Aegialophila. However, despite the importance of pollen evolution in the subtribe, a comprehensive study of the pollen of the involved genera with electron microscopy was lacking. Therefore, we have carried out a survey of pollen morphology and ultrastructure in a wide sample of the genera, using both scanning and transmission electron microscopy. Our results suggest that pollen type of the Carthamus complex is homogeneous and should be classified as a new pollen type in the classification of Wagenitz. Pollen type of Aegialophila shows strong similarities with the Centaurea scabiosa pollen type of Wagenitz, but there are slight differences in shape and in ultrastructure of the exine. These differences are evaluated, together with morphological and molecular evidence; the authors conclude that similarities are the result of parallel evolution and that pollen of Aegialophila could be considered a new pollen type. Some considerations are made on the placement of the new types in the cadre of pollen and molecular evolution in the subtribe Centaureinae.