Birch tree pollen. Coloured scanning electron micrograph (SEM) of pollen grains (yellow) from a birch tree (Betula sp.). Pollen grains contain the male sex cells from a flowering plant. In the process of pollination, the pollen grains are transported from a flower's anthers to the female reproductive parts of a plant. This allows the female and male sex cells to combine in the formation of a seed. Birch trees are deciduous trees found mostly in the temperate areas of the Northern Hemisphere. Magnification: x1600 at 10 centimetres wide.