Elementary species and retrograde varieties are easily recognizable. Ever-sporting varieties on the contrary are far less obvious, and in many cases their hereditary relations have [431] had to be studied anew. A clear analogy between them and corresponding types of wild plants has yet to be pointed out. There can be no doubt that such analogy exists; the conception that they should be limited to cultivated plants is not probable. Striped flowers and variegated leaves, changes of stamens into carpels or into petals may be extremely rare in the wild state, but the "five-leaved" clover and a large number of monstrosities cannot be said to be typical of the cultivated condition. These, however, are of rare occurrence, and do not play any important part in the economy of nature. In order to attain a better solution of the problem we must take a broader view of the facts. The wide range of variability of ever-sporting varieties is due to the presence of two antagonistic characters which cannot be evolved at the same time and in the same organ, because they exclude one another. Whenever one is active, the other must be latent. But latency is not absolute inactivity and may often only operate to encumber the evolution of the antagonistic character, and to produce large numbers of lesser grades of its development. The antagonism however, is not such in the exact meaning of the word; it is rather a mutual exclusion, because one of the opponents simply takes the place of the other when absent, or supplements [432] it to the extent that it may be only imperfectly developed. This completion ordinarily occurs in all possible degrees and thus causes the wide range of the variability. Nevertheless it may be wanting, and in the case of the double stocks only the two extremes are present. It is rather difficult to get a clear conception of the substitution, and it seems necessary to designate the peculiar relationship between the two characters forming such a pair by a simple name. They might be termed alternating, if only it were clearly understood that the alternation may be complete, or incomplete in all degrees. Complete alternation would result in the extremes, the incomplete condition in the intermediate states. In some cases as with the stocks, the first prevails, while in other cases, as with the poppies, the very extremes are only rarely met with. Taking such an alternation as a real character of the ever-sporting varieties, a wide range of analogous cases is at once revealed among the normal qualities of wild plants. Alternation is here almost universal. It is the capacity of young organs to develop in two diverging directions. The definitive choice must be made in extreme youth, or often at a relatively late period of development. Once made, this [433] choice is final, and a further change does not occur in the normal course of things.