Protandry

Campanula species

Male organs open earlier than female flowers (protandry), and there is a possibility of selfing late during anthesis. A) Bud stage: the anthers, which form a ring around the style, deposit pollen on the middle and upper part of the style, B) Early anthesis: The style has elongated, and the filaments started to curl. No pollination is possible at this stage, since the stigma lobes are closed. C) Middle Anthesis: Stigma lobes have split open and are receptive and the anthers have withered. At this stage outcrossing occurs. D) Late anthesis: The stigma lobes have continued to grow, the lobes curving further and contact the remaining pollen left in the upper part of the style. Autogamy may occur.

Campanula
1 - The breeding system of Campanula species (after Faegri and van der Pjil 1979)