Pollen grains in Pinus are monosaccate. In Pinus, pollen grain is unicellular, three layered -outer exine, the middle exo-intine and innermost intine. The exine is cuticularized. It covers the spore only on one side. The rest of spore is covered by the exo-intine. The latter separates from the intine on the side where spore have been in contact with other spores in the tetrad and becomes inflated into two balloon-like expansions or wings. The wings or sacci are separated from the body or the corpus by the saccate hexine or the inner layer of exine.