Colpi are fissure-like apertures while pores are round. The monocolpate type developed into two, possibly even three different directions. It is the direct precursor of the anaporate and maybe also of the polyporate pollen type. The more complex series leading to the polyporate and the polyrugate pollen starts with the monocolpate pollen, too. The point of ramification is the tricolpate pollen (according to A. TAKHTAJAN, 1959).