Chap. XT. OF THE CHAPTER. 407 



several cases were given of partial or complete reversion, both 

 with hybrid and mongrel plants ; hence we may suspect that 

 the strong tendency in the Chrysanthemum, for instance, to 

 produce by bud-variation differently-coloured flowers, results 

 from the varieties formerly having been intentionally or acci- 

 dentally crossed ; and that their descendants at the present day 

 still occasionally revert by buds to the colours of the more 

 persistent parent-varieties. This is almost certainly the case 

 with Bollisson's Unique Pelargonium ; and so it may be to a 

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

 "broken colours" of Tulips. 



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

 reversion, but to spontaneous variability, such as so commonly 

 occurs with cultivated plants when 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 varieties of fruit, it is scarcely possible 

 to believe that all these variations are reversions to former 

 parents. 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 Imatophyllum, &c, there is no 

 known natural species or seedling variety, from which the cha- 

 racters in question could have been derived by crossing. We 

 must attribute all such cases to actual variability in the buds. 

 The varieties which have thus arisen cannot be distinguished 

 by any external character from seedlings ; this is notoriously the 

 case with the varieties of the Kose, Azalea, and many other 

 plants. It deserves notice that all the plants which have yielded 

 bud -variations have likewise varied greatly by seed. 



These plants belong to so many orders that we may infer 

 that almost every plant would be liable to bud-variation if placed 

 under the proper exciting conditions. These conditions, as far 

 as we can judge, mainly depend on long-continued and high 

 cultivation ; for almost all the plants in the foregoing lists are 

 perennials, and have been largely propagated in many soils 

 and under different climates, by cuttings, offsets, bulbs, tubers, 

 and especially by budding or grafting. The instances of annuals 



