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 beetle Pollen beetle Pollen beetle is an informal term for any species of beetle associated intimately with suitably pollen-rich species of flowers. Typically such a beetle is adapted to the pollen as a major part of its diet. Species in at least sixteen families of the order Coleoptera could be counted as pollen beetles, and "pollen beetle" also is a common name for some such species. Many insects of small to modest size benefit from feeding on pollen of suitable plants; pollen tends to be rich in protein, plentiful in season and easily available. Many plants, such as some members of