570 THE GENESIS OF NEW FORMS AS A RESULT OF CROSSING. 



reappear in juxtaposition (as in the Bizzaria), but are united or fused together. 

 Whether the case of Bergamot Pears, which are striped green and yellow, and that 

 of the half dark- and half light-coloured grapes, of which a few occur occasionally 

 in otherwise ordinary bunches of the fruit, are to be looked upon as parallel 

 phenomena to that of the Bizzaria must remain uncertain until it has been ascer- 

 tained to what particular crosses of the various species of Pyrus and Vitis the 

 innumerable Pear-trees and Vines now cultivated owe their origin. 



Over and over again gardeners have asserted that hybrids may also be pro- 

 duced by budding and grafting, and in order to distinguish plants so arising from 

 those which are the result of a cross {i.e. from true hybrids), they are called graft- 

 hybrids. One of these plants, a Laburnum named Cytisus Adamii, which exhibits 

 a curious mixture of the characteristics of Cytisus Laburnum (the ordinary yellow 

 Laburnum) and Cytisus purpureus in the same individual, has been the subject of 

 lively discussion in scientific circles. It is indeed difficult to imagine anything 

 more curious than a plant of Cytisus Adami. Most of the flowers derive their 

 characters equally from both parent-forms; the calyx is not so thickly clad 

 with silky hairs as in C. Laburnum nor so smooth as in C. purpureus, and the 

 corollas are of a dirty-red colour, compounded of the purple of C. purpureus 

 and the yellow of C. Laburnum. But the curious thing is that on many of the 

 racemes a few blossoms of difierent appearance are interspersed amongst these red 

 flowers, some having yellow corollas and silky-haired calices as in C. Laburnum, 

 and others, still more remarkable, having half their petals like C. purpureus and 

 half like C. Laburnum, or a third of their petals like C. purpureus and two-thirds 

 like G. Laburnum, or some one of many other combinations. According to 

 Schnittspahns, this anomalous form of Cytisus was first produced at Vitry, near 

 Paris, in the year 1826, by a grower named Adam, who inserted a bud of C. pur- 

 pureus into a stock of G. Laburnum. The shoot which sprang from the bud was 

 not a pure branch of C. purpureus, but had characteristics derived both from 

 C. purpureus and from C. Laburnum. Buds for propagating G. Adami were sent 

 from Vitry to gardens all over Europe, and were in some cases inserted into stocks 

 of C. Laburnum, and in other cases into stocks of G. Jacquinianus and C. alpinus. 

 In many cases gardeners grafted buds of G. purp)ureus in addition to those of 

 G. Adami on to the same stocks, and thus produced shrubs of most extraordinary 

 appearance. Of the branches some resembled C. Laburnum, C. Jacquinianus, or 

 G. alpinus, others Cytisus Adami, and others again G. purpureus; and amongst 

 the racemes were many which bore the ordinary flowers of G. Adami, interspersed 

 with a few blossoms of C. Laburnum, and others in whose flowers a mixture of 

 the properties of C. Laburnum and G. purpureus was apparent. The fact of main 

 interest, however, is that cuttings from Adam's original plant (the alleged graft- 

 hybrid of G. Laburnum and G. purpureus) should bear not only flowers of an 

 intermediate type (as might be looked for in a hybrid), but that on certain branches 

 the flowers break back (or revert) to the pure form of one or other of the parents, 

 or that a single flower should exhibit on one half the characters of one parent and 



