<?hap.XX. SELECTION. 217 



so manv flowers and the number of the varieties which have 

 been raised is all the more striking when we hear that the 

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

 only from the year 1545.* 



87 



Effects of Selection, as shown hy the parts most valued hy 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 distinct 

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

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

 ever part man values most, that part will be found to present the 

 greatest amount of difference. With trees cultivated 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, chesnuts, &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 in these same plants of 

 the other parts. 88 



In order to judge how far my own impression on this subject 

 was correct, I cultivated numerous varieties of the same species 

 close to each other. The comparison of the amount of dif- 

 ference between widely different organs is necessarily 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 resemble each other in their 

 flowers, capsules, and seeds. In seven varieties of the radish, 

 the roots differed greatly in colour and shape, but no difference 



8 7 Prescott's ' Hist, of Mexico,' vol. 63, 67, 70. In my tenth and eleventh 



ii. p. 61. chapters I have given details on the 



8S Sageret, ' Pomologie Physiolo- potato ; and I can confirm similar re- 



giqne,' 1830, p. 47; Gallesio, 'Teoria marks with respect to the onion. I have 



della Eiproduzione,' 1816, p. 88 ; also shown how far Naudin concurs 



■Crodron, ' De l'Espece,' 1859, torn. ii. pp. in regard to the varieties of the melon. 



