408 



CONCLUSION AND SUMMARY 



Chap. XI 



varying by buds, or producing on the same plant differently 

 coloured flowers, are comparatively rare : Hopkirk 140 has seen 

 this with Convolvulus tricolor ; and it is not rare with the Balsam 

 and annual Delphinium. According to Sir R. Schomburo-k 

 plants from the warmer temperate regions, when cultivated 

 under the hot climate of St. Domingo, are eminently liable 

 to bud- variation ; but change of climate is by no means a neces- 

 sary contingent, as we see with the gooseberry, currant, and 

 some others. Plants living under their natural conditions are 

 very rarely subject to bud- variation : variegated and coloured 

 leaves have, however, been occasionally observed ; and I have 

 given an instance of the variation of buds on an ash-tree ; but 

 it is doubtful whether any tree planted in ornamental grounds 

 can be considered as living under strictly natural conditions. 

 Gartner has seen white and dark-red flowers produced from the 

 same root of the wild Achillea millefolium ; and Prof. Caspary 

 has seen Viola lutea, in a completely wild condition, bearing 

 flowers of different colours and sizes. 141 



As wild plants are so rarely liable to bud- variation, whilst 

 highly cultivated plants long propagated by artificial means 

 have yielded by this form of reproduction many varieties, we are 

 led through a series such as the following, — namely, all the eyes 

 in the same tuber of the potato varying in the same manner, — 

 all the fruit on a purple plum-tree suddenly becoming yellow, 

 — all the fruit on a double-flowered almond suddenly becoming 

 peach-like, — all the buds on grafted trees being in some very 

 slight degree affected by the stock on which they have been 

 worked, — all the flowers on a transplanted heartsease changing 

 for a time in colour, size, and shape, — we are led through such 

 facts to look at every case of bud-variation as the direct result 

 of the particular conditions of life to which the plant has been 

 exposed. But if we turn to the other end of the series, namely, 

 to such cases as that of a peach-tree which, after having been 

 cultivated by tens of thousands during many years in many coun- 

 tries, and after having annually produced thousands of buds, all 

 of which have apparently been exposed to precisely the same 

 conditions, yet at last suddenly produces a single bud with its 

 whole character greatly transformed, we are driven to an opposite 



140 'Flora Anomala.'p. 164. . 



141 ' Schriften der Phys.-Okon. Gesell. zu Konigsberg,' Band vi., Feb. 3, I860, s. 4. 







He 



