The different stages of germination of the megaspores in Azolla filliculoids have been observed by GMA segment technique and scanning electron microscopy. The entire germination process can be described by four stages. (1) The pre-germination stage which covers the interval from the soaking of the megasporocarps to the floating and division of the prothallial mother cell. It is characterized by the gradual consumption of the grannular reserves acted upon by the hydrase. (2) The stage of prothallus development in the course of which the prothallial mother cell divides and develops into the prothallus. In the region between the prothallial center and the periphery

two to three archegonium mother cells are formed

each of which is recognizable by its bulky size

a large nucleus

and dense cytoplasm. (3) The stage of archegonium formation which commences at the first sign of division in one of the archegonium mother cells and terminates at the appearance of two to three archegonia of different maturity. During this period

the prothallus continues to grow and protrudes out of the megaspore through the trilete aperture. (4) The stage of embryogehic development which lasts from the fertilization of the mature egg until the formation of all the organ parts of the sporeling. Initially

the zygote undergoes division to form a quadrand. Of the two cells near the neck

one gives rise to a single cotyledon and the other to the shoot

which subsequently grow into young leaf and root. Of the two basal cells

one forms the foot and the other gives rise to the initial root.In addition to the above observations

the relationships between morphogenesis and function are discussed