Pollen grains. Coloured scanning electron micrograph (SEM) of pollen grains. The outer wall (exine) is highly sculpted, which might aid the dispersal of the pollen grains, by improving their adherence to pollinators. The characteristic surface of pollen grains is used by botanists to recognise and classify plants. Each pollen grain contains a male gamete (reproductive cell) that is intended to fertilise an egg or ovule (female gamete), and initiate the formation of a seed for a new plant.