XVI International Botanical Congess

We have found that deviant pollen forms may have an identical aperture arrangement even in different subclasses of the Angiosperms. Together with common forms, they can be arranged in such a way as to give a succession, in which one common form gradually transforms to another one (colpate, rugate, porate or sulcate). Thus, the succession of Angiosperm pollen forms has a continuous and regular pattern. This means that 1) this succession cannot be described as morphological diversity having, by definition, a discrete and random pattern and should be considered as a variety with any possible pattern, 2) this variety cannot have resulted from divergence, natural selection and phyletic evolution. There is some evidence that this succession reflects regularities of pollen aperture patterning in ontogenesis. What do we study then?