Chap. XI. OF THE CHAPTER. 439 



Chrysanthemum revert to the aboriginal yellow tint. Many 

 other cases included in the list are probably due to the plants 

 being of crossed parentage, and to the buds reverting either 

 completely or by segments to one of the two parent-forms. 154 



We may suspect that the strong tendency in the Chrysan- 

 themum to produce by bud- variation differently-coloured 

 flowers, results from the varieties having been at some time 

 intentionally or accidentally crossed; and this is certainly 

 the case with some kinds of Pelargonium. So it may be to a 

 large extent with the bud-varieties of the Dahlia, and with 

 the " broken colours " of Tulips. When, however, a plant 

 reverts by bud-variation to its two parent forms, or to one of 

 them, it sometimes does not revert perfectly, but assumes a 

 somewhat new character, — of which fact, instances have been 

 given, and Carriere gives 155 another in the cherry. 



Many cases of bud-variation, however, cannot be attributed 

 to reversion, but to so-called spontaneous variability, as is 

 so common with cultivated plants raised from seed. As a 

 single variety of the Chrysanthemum has produced by buds 

 six other varieties, and as one variety of the gooseberry has 

 borne at the same time four distinct kinds of fruit, it is 

 scarcely possible to believe that all these variations are due to 

 reversion. We can hardly believe, as remarked in a previous 

 chapter, that all the many peaches which have yielded 

 nectarine-buds are of crossed parentage. Lastly, in such 

 cases as that of the moss-rose, with its peculiar calyx, and of 

 the rose which bears opposite leaves, in that of the Imanto- 

 phyllum, etc., there is no known natural species or variety 



154 It may be worth while to call version to a character not originally 



attention to the several means by gained by a cross, but which had 



which flowers and fruit become long been lost, as with white-flowered 



striped or mottled. Firstly, by the varieties, which we shall hereafter see 



direct action of the pollen of another often become striped with some other 



variety or species, as in the cases colour. Lastly, there are cases, as 



given of oranges and maize. Secondly, when peaches are produced with a 



in crosses of the first generation, half or quarter of the fruit like a 



when the colours of the two parents nectarine, in which the change is 



do not readily unite, as with Mirabilis apparently due to mere variation, 



and Dianthus. Thirdly, in crossed through either bud or seminal 



plants of a subsequent generation generation. 



by reversion, through either bud or 153 ' Production des Varieties, p. 



«aninal generation. Fourthly, by re- 37. 



