image of pollen grains from a variety of common plants: sunflower (Helianthus annuus), morning glory (Ipomoea purpurea), prairie hollyhock (Sidalcea malviflora), oriental lily(Lilium auratum), evening primrose (Oenothera fruticosa), and castor bean (Ricinus communis).]]]](the purple one)]]Pollen is a fine to coarse powder consisting of microgametophytes (pollen grains), which produce the male gametes (sperm cells) of seed plants. The pollen grain with its hard coat protects the sperm cells during the process of their movement between the stamens of the flower to the pistil of the next flower. The structure of pollen 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) cell