Evolutionary patterns of the internal structures of generative organs in angiosperms are considered in light of the idea on their close dependence on the appearance of angiospermy – formation of the ovary closed cavity by carpels– macrosporophylls. A characteristic feature of the sexual process in gymno- and angiosperms is the independency of water for fertilization, unlike all lower plants and pteridophytes. The main direction of the further evolution of the sexual process consisted in the modification for adaptations that ensure the successful fertilization in new conditions. The guidelines and levels of evolution include aromorphosis, allomorphosis, specialization and reduction which are considered to be concrete examples of microstructure of generative organs.