This section is from the book "The Gardener V1", by William Thomson. Also available from Amazon: The New Organic Grower: A Master's Manual of Tools and Techniques for the Home and Market Gardener.
"We appear to be fast approaching a state of things in relation to Horticulture, when we shall not have any description of green-foliaged plant of which there will not also be its variegated counterpart. The extent to which this characteristic has developed itself in hardy plants especially is something remarkable, whether in the case of cultivated or wild species and varieties. The variegated Plantain is a well-known instance; and recently I gathered from the roadside a plant of the Cineraria palustris showing partial variegation, that has since developed into an entirely creamy-white-coloured foliage. For the first time, to my knowledge, I have this winter met with a variegated Sweet William, having well-defined streaks of white running the whole length of the leaves; and again, although not quite so novel in appearance, several plants of variegated Primula have come amongst my batch of this popular winter and spring flower. The mention of a variegated Cabbage will cause many to smile, but I can assure them that as a white-foliaged plant for greenhouse decoration in the winter it is almost unrivalled, as the variegation is of the whitest character, and might justly be described as snow white, the leaves being broadly edged - in fact, quite eclipsing the variegated Hydrangea. A. D.