Background

Research on the morphology and development of pollen and tapetum has contributed to understanding the evolution of these characters and elucidating phylogenetic relationships among seed plants.
Over evolutionary time, the morphology of angiosperm pollen has evolved toward an increasing number of apertures, among other things. From a neo-Darwinian point of view, this means that (i) some polymorphism for aperture number must exist and (ii) there must be some fitness increase associated with increasing the aperture number. Pollen types with different aperture numbers often occur in the same species.
Although the majority of flowering plants achieve pollination by exploiting the food‐seeking behavior of animals, some use alternative ploys that exploit their mate‐seeking behavior. Sexual deception is currently known only from the Orchidaceae and almost always involves pollination by male hymenoptera.
Pollen grains are the carriers of the male gametes or their progenitor cell, in higher plants. They also are important tools for paleoclimatic reconstruction. They reflects the ecology of their parent plants and their habitats and provide a continuous record of their evolutionary history.