be possible to give more than an outline of the reproductive schemes to be observed in a few typical species. These life histories must not be taken as necessarily applying to all the related plants. None the less, by a careful study of the species described we may receive a fair conception of the habits of the class to which it belongs. Incidentally it may be mentioned that even a low-power microscope will be an enormous help in studying the life histories of the Vascular Cryptogams; but if this is not possible, a pocket-lens will help to a better understanding of many of the points described.

For the study of the life history of a Fern one cannot do better than take the commonest of our native species, the Male Fern (Nephrodium filix-mas). Seeing that the general aspects of the plant are fully described in a later chapter, there is no need to enter into such matters at the present moment. We may, however, examine a fertile leaf of the Fern in order that we may start at the beginning of a really interesting romance. A very small magnification of the brown patches on the back of the frond, which we remember are called sori, will reveal their true character. After removing the kidney-shaped cover (indusium) we shall be able to see the spore cases or sporangia quite clearly. Each of these consists of a capsule borne on the end of a stalk. These sporangia are seen to grow out from the sides of a mass of special tissue, known as the placenta, from which the indusium really arises. On occasions a curious club-shaped hair which secretes resin can be observed on the stalks of the sporangia. There seems to be no satisfactory explanation as to the part which this process plays. The capsule of the sporangium is much flattened, and has not been inaptly compared to a watch-case. Its wall is very thin, being composed of a single layer of cells. Around the edges of the little case there is a row of large and thickened cells which form the ring or annulus. Here it may be mentioned again that the structure of this annulus varies greatly in the different families, and is often a useful distinguishing feature. To return to our Male Fern, the annulus is plainly seen to start from the stalk of the sporangium at one side of the capsule, and it can be traced right over the top to a situation about half-way down on the other side. The chief business of the annulus is to bring about the opening of the sporangium in such a way that the spores are violently expelled. This happens in the following manner. When the contents of the sporangium are mature the wall of the capsule, and especially the cells forming the annulus, begin to lose water. The sides of the capsule start to draw inwards, and ultimately the annulus suddenly straightens out and the sporangium is torn open, the actual rupture taking place just at the base of the ring.

The manner in which the spores originate in the sporangium calls for comment. In the case of the Male Fern these arise owing to the repeated division of a single cell. At a certain stage in the process there are produced what are known as mother cells. Ultimately these divide twice, and the resulting cells represent the spores. When ripe, the spores become kidney-shaped and the wall of the cell takes on a rich brown colour. In the different kinds of Ferns, the form of the spore and the sculpturing of its walls vary a great deal. Thus the spores may be globular, oval, or angular in shape; whilst the exterior may be quite plain, or, perhaps, most beautifully marked. The number of spores produced in the sporangium of a Male Fern is usually some forty-eight to sixty-four, although in other species there might be less than the lower figure or more than the higher. To the naked eye the spores appear to be so much dust, and as they are comparatively light they float away on the breezes, and often enough travel for a considerable distance before coming to rest. As a rule the bursting of the sporangia takes place during dry weather. There is a real advantage in this, for when the spores are damp they hang together in masses and in such a state a wide dispersal would be out of the question.

The best thing that can happen to the spore is that it should settle upon some moist soil. Here it may be mentioned a most instructive experiment is the sowing of a few fern spores. This may be carried out in ordinary garden soil, although it is wise to sterilize it before use. All soil contains the germs of such organisms as mould which, in cultivation at any rate, is especially destructive to developing spores. The plan is to bake the mould in an oven until it is so hot that one cannot bear to touch it. We shall get any number of spores from the fertile leaf of a Male Fern by just tapping the frond whilst holding it over the surface of the soil. Do not scatter the spores too thickly, or it will be difficult to examine the stages of development, and remember also that the soil should be moist at the start. The results of this spore culture are always more satisfactory if the soil is covered with a bell-glass—an ordinary tumbler would do if nothing better is available. Water must be given as necessary, though do not swamp the soil; the best plan is to let the liquid in a few drops at a time.

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.

The manner of fertilization may be briefly outlined, although the observation of this is beyond the ordinary student. With Ferns, as is the case with nearly all the Cryptogams, the fertilization takes place under water; the moisture may be the outcome of heavy rain or even dew. However that may be, as soon as the underside of the prothallus has become thoroughly wetted the antheridia open, and certain little bodies called spermatozoids are allowed to escape. These are exceedingly active, and are in the form of spirally coiled bodies with a number of fine threads (cilia) at one end. The same moisture which caused the antheridia to open also brings about the opening of the archegonia. Some time ago it was shown that the spermatozoids steered a decided course towards the archegonia, but the reason for this has only been comparatively recently explained. At the mouth of the archegonia there is a viscid drop which almost certainly contains chemical substances attractive to the spermatozoids. Although the nature of the substance is not