Pollen magnification to see detail. The study of pollen is called palynology and is highly useful in paleoecology, paleontology, archaeology, and forensics. Pollen in plants is used for transferring haploid male genetic material from the anther of a single flower to the stigma of another in cross-pollination. In a case of self-pollination, this process takes place from the anther of a flower to the stigma of the same flower. Pollen itself is not the male gamete. Each pollen grain contains vegetative (non-reproductive) cells (only a single cell in most flowering plants but several in other seed plants) and a generative (reproductive)
Pollen tube by recognition and hydration of the pollen that allows for germination of the tube and ultimate growth. In the pollen grain, the generative cell gives rise to the sperm, whereas the vegetative cells have a tube cell that grows the pollen tube. There is competition in this step as many pollen grains may compete to reach the egg. The stigma plays a role in guiding the sperm to a receptive ovule, in the case of many ovules. Only compatible pollen grains are allowed to grow as determined by signaling with the stigma. Some plants have mechanisms in place to prevent