The third, and at present the most acceptable theory, is that we have in the nectarine from the peach what De Vries calls a retrogressive mutation. That is, an active character, in this case pubescence on the fruit, becomes latent and appears to be lost--a type of mutation frequent among cultivated plants. The nectarine, then, is a peach with one character subtracted. When the nectarine yields a peach, the character is restored. The one is a negative, the other a positive step; one is retrogressive, the other progressive mutation. The speculations as to what causes these mutations are as yet too vague to be profitable. Probably we can never make use of the cause by which mutations arise or of the conditions leading to them until we can induce these strange variations. That they are due to disturbances in the processes of cell-division is the theory now current--sufficiently comprehensive and sufficiently vague to be a most convenient explanation, at any rate. Nectarines do not attain the perfection in New York reached west of the Rocky Mountains. The trees, possibly, are a little less manageable in the orchard, less vigorous and certainly more susceptible to pests. Nectarines, in particular, suffer more than peaches from the scourge of the crescent sign, curculio, a pest which finds all smooth-skinned stone-fruits much to its taste and the nectarine more than others. Then, too, whether fresh, canned or dried, fruit-buyers in America prefer the peach. This discrimination in favor of the peach is largely due to lack of knowledge of the nectarine, which, though different from the commoner fruit, is equally delectable, fresh or preserved, and certainly is a handsomer product preserved either by canning or evaporating. Indeed, the dried nectarine, with its beautiful, translucent, amber hue is the most attractive of all cured fruits. The nectarine-industry, however, belongs to California, where all conditions favor production, canning and curing. [Illustration: KENTUCKY (Nectarine)] [Illustration: NEWTON (Nectarine)] PRUNUS DAVIDIANA (Carrière) Franchet _P. Davidiana_ Franchet _Nouv. Arch. Mus. Paris_ ser. 2, =V=:255 (_Pl. David._ =1=:103). 1883. _Persica Davidiana_ Carrière _Rev. Hort._ 74. 1872. _Prunus Persica_ var _Davidiana Maximowicz Bul. Acad. Sci. St. Petersbourg_ =29=:81; _Mel. Biol._ =11=:667. 1883. Tree attaining a height of twenty-five feet on the Station grounds, vigorous, upright, with slight spreading tendency, dense-topped, hardy in tree but not in flower-bud, unproductive; trunk stocky; branches thick, smooth, bronze-colored; branchlets slender--inclined to rebranch, long, with rather short internodes, ash-gray mingled toward the base with dark brown, glabrous, with inconspicuous, small, slightly raised lenticels.