VARIEGATION, among botanists and florists, the act of streaking or diversifying the leaves, &c. of plants and flowers with several colours.
Variegation is either natural or artificial. Of natural variegation there are four kinds; the first shewing itself in yellow spots here and there in the leaves of plants called by gardeners the yellow blotch. The second kind, called the white blotch, marks the leaves with a great number of white spots or stripes; the whitest lying next the surface of the leaves, usually accompanied with other marks of a greenish white, that lie deeper in the body of the leaves. The third, and most beautiful, is where the leaves are edged with white, being owing to some disorder or infection in the juices, which stains the natural complexion or verdure of the plant. The fourth kind is that called the yellow edge.
Artificial variegation is performed by inarching or inoculating a striped or variegated plant into a plain one of the same sort; as a variegated common jessamin into a plain, common, Spanish, Brazil, or Indian jessamin.
A single bud or eye, Mr Bradly observed, being placed in the cleft of a disintegrated tree, where it can only receive nourishment from the vitiated juices, will become variegated proportionably to the nourishment it draws; and will partake more of the white and yellow juice, than if a branch shall be inarched, the bud having nothing to nourish it but the juices of the plant it is inoculated on; whereas a cylon inarched is fed by the striped plant, and the healthful one.
As to the natural stripes and variegations, there are some particular circumstances to be observed: 1. That some plants only appear variegated or blotched in the spring and autumn, the stains disappearing as they gather strength: of this kind are rue, thyme, and marjoram. 2. Some plants are continually blotched in the spongy part of their
their leaves, the sap-vessels all the time remaining of a healthful green; which, being strengthened by rich manure, or being inarched in healthful plants, throw off the distemper. 3. In other plants, the disease is so rooted and inveterate, that it is propagated with the seed; such are the arch-angel, water-betony, bark-cress, borage, striped cellary, and fycomore; the sides of which produce striped plants.