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
Flower chafer Flower chafer Flower chafers are a group of scarab beetles, comprising the subfamily Cetoniinae. Many species are diurnal and visit flowers for pollen and nectar, or to browse on the petals. Some species also feed on fruit. The group is also called fruit and flower chafers, flower beetles and flower scarabs. There are around 4,000 species, many of them still undescribed. By morphological characters, the adults can be separated from the other scarabs by the combination of the following characters: epipleuron easily recognizable, border lateral of elytra sinuate and antennal insertion visible from above. Twelve tribes are presently recognized: Cetoniini,