Botanical Gazette 4(6): 165-166 (June, 1879)
Of The Scion On The Stock
It is now very well known that many of our variegated varieties of green house Abutilons are produced by budding. A species with a variegated leaved form is grafted on another species, and from the branches which spring from the stock beneath the bud or graft, come out in some cases variegated ones—the same as the stock in all cases. There is no hybridity, only the variegation is communicated to the sprout from the stock.
Three years ago a bud of the blood-leaved variety of Betula alba was put into a strong stock of B. alba, var. populifolia, our American form. The following spring the bud made a growth of nearly a foot in length, when a careless laborer pushing against it, knocked the growing shoot completely out. Over the place where it grew a bud of the cut-leaved Birch was inserted, which, growing, caused the stock to be preserved. Last spring, several inches below the place where the original bud of the blood-leaved variety had been torn out, a branch of a blood-leaved color pushed forth. It attained a height of nearly two feet the past summer, and the stock still shows the scar of the original bud. That such transfusion of character can be carried downward in the stock is not new, as already noted in Abutilon, but I think it is new that this coloring principle can exist in the stock for ten months after all the foliage has been destroyed, and nothing but a portion of the original bark of the bud remained.
Another novel point is that whereas in other cases only the "variegating material" has been transfused downwards, the specific, or it may be varietal, character remaining intact; in this case the new bud from the populifolia stock is the true European alba, showing that in this case more character than that of mere coloring has been transmitted through the structure of the stock. I may remark that many botanists receive B. populifolia as but a variety of B. alba. As long as it is not possible to define what is a species, there may be an allowable difference of opinion, but it seems to me there are as many permanent distinctions as in many other universally acknowledged species of plants. There is one distinction which I have never seen noted. In B. populifolia the leaves spread flat at once in expanding, while those of B. alba are bent upward until mature. I enclose samples from the stock and blood-leaved shoot to illustrate this distinction.—Thos. Meehan.