| Abstract: | Families of the Campanulales-Asterales-complex are characterized by special mechanisms for secondary pollen presentation: pump mechanism, brushing mechanism, deposition mechanism, cup mechanism and combination of cup mechanism with brushing mechanism. These different mechanisms are based on three successive events: elongation of the filaments, opening of the anthers, elongation of the style. The diversity of the mechanisms arises through different auxiliary structures such as an indusium, hairs or an anther tube, and the relative rate and time of filament and style growth. An advantage of secondary pollen presentation lies in the prolongation of the male phase of anthesis through portioned pollen release. A probable phylogeny of the different mechanisms of secondary pollen presentation is proposed (Fig. 7). |
