Pollen morphology and generic relationships in the Valerianaceae

Abstract

Abstract Pollen of representative species of all genera in the Valerianaceae has been examined using light and scanning electron microscopy. The pollen of every genus had many features in common, notably the characteristic halo surrounding the apertures. Other features such as ornamentation, aperture shape and exine layering varied sufficiently for most genera to be recognized by their pollen morphology. Two major groups of genera could be recognized: the Valeriana group which has simple columellae, and the Valerianella group which has elongated, branched columellae at the poles. Pollen morphology can be used to suggest relationships between the genera; many of these relationships corroborate those suggested in other studies, while in other cases new associations are proposed.