1895- BUD-VARIATION AND EVOLUTION. 105 



" When we ask ourselves what is the cause of any particular bud- 

 variation, we are lost in doubt, being driven in some [all ?] cases to 

 look to the direct [or indirect] action of the external conditions of life 

 as sufficient." 



Again, as crossing is common among flowers, so graft-hybrids 

 are possible. One stock or scion may so influence the other as to 

 cause it to produce buds partially or greatly like itself. Seeds of a 

 cultivated scion when grafted on a wild stock may be so affected as 

 to reproduce the wild form. Other instances are well known. 



Mr. Bailey next draws attention to the seminal reproduction of 

 bud-varieties, as, e.g., the moss-rose. On the other hand, as " some 

 seed-varieties will not ' come true ' by cuttings, so also there are some 

 bud-sports which will not." 



Lastly, "in proof of the further similarity of bud- and seed- 

 variations, each class follows the incidental laws of external re- 

 semblance which pertain to the other class. For instance, there are 

 analogous variations in each, giving rise to the same kinds of varie- 

 gation, the same anomalies of cut and coloured foliage, of creeping 

 branches, parti-coloured fruit, and the like . . . The most expert 

 observer is not able to distinguish between bud-varieties and seed- 

 varieties ; the only way of distinguishing the two is by means of the 

 records of their origins." 



Mr. Bailey next discusses more fully the most important point of 

 truly asexual variation as a source of the origin of species. 

 He enumerates several plants which have produced, under culti- 

 vation, many varieties, but have never been known to bear seed — 

 such as the pine-apple, banana, bread-fruit, weeping willow, "top" 

 onion, and horse-radish. Of fruit-trees, he describes the interesting 

 case of the Newtown pippin apple, which has been widely spread by 

 grafting. He tells us that it originated upon Long Island, New 

 York. In Virginia it varied into the " Albemarle Pippin," an 

 inferior kind. It has varied again in the extreme North-Western 

 States, " being much longer, and bearing distinct ridges about the 

 apex." 



This last form has varied again in New South Wales, the ridges 

 becoming more marked, and is called the " Five-crowned Pippin." 

 That the causes are attributable to the environment, such as climate, 

 etc., is obvious, from the fact that " most north-eastern varieties of 

 apples tend to take on the elongated form in the Pacific North- West, 

 to become heavy-grained and coarse -striped in the Mississippi \'alley 

 and the Plains, and to take other characteristic forms in the higher 

 lands of the South Atlantic States." 



He notes the rapidity with which the asexual changes are some- 

 times brought about : " Within two years the Chilian strawberry 

 varied or departed from its wild type so widely as to be indistinguish- 

 able from the common garden strawberry ; so that we have here a 

 most interesting case of sexless evolution, but one in which the 



