In the case of the Male Fern the germination of the spore will start in about eight days, but in other species the period varies. Many of the succeeding stages cannot be intelligently followed except with the aid of a microscope. The first thing which happens to the germinating spore is the development of a root hair which helps in fixing the process to the soil. A system of cell division now commences in the other portion of the spore which results in the formation of a green filament, every cell of which is capable of producing root hairs. This filament is the beginning of the body, known as the prothallus, which is responsible for the sex organs. The process of cell-division goes forward and ultimately results in the development of a green scale measuring, perhaps, an eighth of an inch across at its broadest part. This is the fully-grown prothallus. From the underside arise more root hairs, and it is here also that the antheridia (male organs) and the archegonia (female organs) are produced. As a rule, both kinds of organs occur on the same prothallus, although now and again prothalli have been discovered which are exclusively male or female. The matter is of interest, because it evidences an occasional distinction of sex which has become habitual in some of the Club Mosses. In the case of a perfectly normal prothallus the male organs or antheridia are to be found amongst the root hairs, whilst the female organs or archegonia arise from a cushion, several cells deep, more towards the centre of the process.