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
Corn silk Corn silk is part stigma and part style, providing a female flower surface to which pollen grains can adhere and defining the lengthy path through which the pollen must transmit its genetic material. The stigma is the very tip of the corn silk, which has a larger number of hairs to help pollen to adhere to it. Kernel formation in the cob requires pollination of the external corn silk by wind or insects. Usually several grains of pollen adhere, but only one will successfully participate in fertilization of the ovule to form a corn kernel. For the pollen grain, the