Pollen (microsporocyte, pollen mother cell or meiocyte), after meiotic division. After the formation of the four microspores, which are contained by callose walls, the development of the pollen grain walls begins. The callose wall is broken down by an enzyme called callase and the freed pollen grains grow in size and develop their characteristic shape and form a resistant outer wall called the exine and an inner wall called the intine. The exine is what is preserved in the fossil record. Two basic types of microsporogenesis are recognised, simultaneous and successive. In simultaneous microsporogenesis meiotic steps I and II are completed
Milky spore reproduction of the bacteria inside the grub. Within 7–21 days the grub will eventually die and as the grub decomposes, billions of new spores are released into the soil. Milky spore in the soil is not harmful to beneficial insects, birds, bees, pets, or people; and milky spore, like other bacteria, is highly survivable in drought conditions but suffers in temperatures of Zone 5 and colder. Milky spore Paenibacillus popilliae (formerly "Bacillus popilliae") is a soil-dwelling, Gram-positive, rod-shaped bacterium. It is responsible for a disease (commonly called milky spore) of the white grubs of Japanese beetles. The adult Japanese beetles