Gladiolus flower pollen grains. Coloured scanning electron micrograph (SEM) of pollen grains from the gladiolus flower (Gladiolus sp.). The characteristic outer wall, or exine, 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. Magnification: x700 when printed at 10 centimetres wide.