Characters of stigma in three Aquilegia species
三种耧斗菜属植物柱头的特征

The developmental pattern of stigma in flowering plants has been little studied though it plays an important role in pollen capture. An unusual developmental pattern of stigma was observed in three Aquilegia species (Aquilegia yabeana Kitagawa, A. ecalcarata Maxim. and A. incurvata P. K. Hsiao) with scanning electron microscopy and fluorescence microscopy. The stigmas of Aquilegia flowers were on the ventral sides of the styles, and developed into stigmatic papillae by cells along the ventral slits. During anthesis the receptive surfaces matured in a sequence from the apical towards the basal ends of the styles, and posed for pollinators gradually through the style movement of recurving. Such a developmental pattern may enhance reproductive success by the prolongation of stigma receptivity under the unpredictable pollination environments.