Pollen as large as about 90–100 µm. In angiosperms, during flower development the anther is composed of a mass of cells that appear undifferentiated, except for a partially differentiated dermis. As the flower develops, four groups of sporogenous cells form within the anther. The fertile sporogenous cells are surrounded by layers of sterile cells that grow into the wall of the pollen sac. Some of the cells grow into nutritive cells that supply nutrition for the microspores that form by meiotic division from the sporogenous cells. In a process called microsporogenesis, four haploid microspores are produced from each diploid sporogenous cell
Pollen DNA barcoding atmospheric pollen originating from illegal cannabis farms were successfully detected by scientists which in the future could allow law enforcement officials to narrow down the search areas for illegal farms. Due to the hardy structure of pollen which has evolved to survive being transported sometimes great distances while keeping the internal genetic information intact, the origin of pollen found mixed in ancient substrates can often be determined through DNA barcoding. Honeybees carry pollen as well as the nectar used in their production of honey. For food quality and safety concerns it is important to understand the plant providence of human-consumed