1. The sporogenous tissue develops from a single hypodermal archesporial cell. 2. As the successive sporogenous cells are formed, each retains its individuality throughout the development of the sporogenous tissue. 3. Divisions in the sporogenous tissue are simultaneous up to the mother-cell stage. 4. Beginning with the mother-cell stage, the sporogenous mass separates successively into blocks of cells in the same order in which the earlier cells were formed. 5. The blocks develop independently, and at a different rate in the same sporangium, though all cells of one block develop at the same rate. Whatever stimulus caused the simultaneity of division in early sporogenous tissue, is interfered with by separation of the cells into disjoined groups. 6. The progressive separation of the sporogenous mass is probably caused by the digestion of the middle lamellae. 7. All mother-cells produce spores. 8. The tapetum is of non-sporogenous origin. 9. With the separation of mother-cell groups, the tapetum grows rapi...