A typical anther of a stamen contains four microsporangia where the microsporangia form sacs or pockets in the anther then these undergo meiosis to form haploid spores (the number of complete sets of chromosomes in a cell).
The microsporangia form sacs or pockets (locules) in the anther (anther sacs or pollen sacs). These undergo meiosis to form haploid spores. Each microsporangium is lined with a nutritive tissue layer called the tapetum and initially contains diploid pollen mother cells. 
