202 SELECTION. Chap. XX. 



earliest known flower-garden in Europe, namely at Padua, 

 dates only from the year 1545.^^ 



Effects of Selection, as shown by the parts most valued by man 

 presenting the greatest amount of difference. — The power of long- 

 continued selection, whether methodical or unconscious, or 

 both combined, is well shown in a general way, namely, by 

 the comparison of the differences between the varieties of dis- 

 tinct species, which are valued for different parts, such as for 

 the leaves, or stems, or tubers, the seed, or fruit, or flowers. 

 Whatever part man values most, that part will be found to 

 present the greatest amount of difference. AVith trees culti- 

 vated for their fruit, Sageret remarks that the fruit is larger 

 than in the parent-species, whilst with those cultivated for 

 the seed, as with nuts, walnuts, almonds, chestnuts, &c., it is 

 the seed itself which is larger ; and he accounts for this fact 

 by the fruit in the one case, and by the seed in the other, 

 having been carefully attended to and selected during many 

 ages. Gallesio has made the same observation. Godron 

 insists on the diversity of the tuber in the potato, of the bulb 

 in the onion, and of the fruit in the melon ; and on the close 

 similarity of the other parts in these same plants.^'* 



In order to judge how far my own impression on this 

 subject was correct, I cultivated numerous varieties of the 

 same species close to one another. 1'lie comparison of the 

 amount of difference between widely different organs is neces- 

 sarily vague ; I will therefore give the results in only a few 

 cases. We have previously seen in the ninth chapter how 

 greatly the varieties of the cabbage differ in their foliage and 

 stems, which are the selected parts, and how closely they re- 

 semble one another in their flowers, capsules, and seeds. In 

 seven varieties of the radish, the roots differed greatly in 

 colour and shape, but no difference whatever could be detected 

 in their foliage, flowers, or seeds. Now what a contrast is 



*'^ Prescott's ' Hist, of Mexico,' vol. eleventh chapters I have given details 



ii. p. 61. on the potato ; and I can confirm 



*^ Sagaret, ' Pomologie Physiolo- similar remarks with respect to the 



gique,' 1830, p. 47 ; Gallesio, ' Teoria onion. I have also shown how far 



della Ripi-oduzione,' 1816, p. 88 ; Kaudin concurs in regard to the 



Godron, ' De I'Espfece,' 1859, torn. ii. varieties of the melon. 

 pp. 63, 67, 70. In my tenth and 



