Pollen is a fine to coarse powder consisting of microgametophytes (=pollen grains), which produce the male gametes (sperm cells) of seed plants. Wind pollinated plants have to make billions of pollen grains if one might succeed – it’s an intimate improbably lottery!
A hard coat covering the pollen grain protects the sperm cells during the process of their movement between the stamens of the flower to the pistil of the next flower. Pollen grain morphology is breathtakingly divers. Wind pollinating plants generally produce small grains with a smooth surface, thereby increasing the probability of successful fertilization.