iv VARIETIES DUE TO CULTIVATION 177 



type in species cultivated in countries where the wild 

 form does not exist. 



The foregoing facts show that some modification is 

 due to cultivation, in cultivated plants, since some 

 species exist which are not recognised in the wild 

 state, such as indian-corn, sugar-cane, wheat, etc. But 

 numerous modifications are met with, when we con- 

 sider our cultivated species themselves, and investigate 

 the orgin of the varieties they exhibit. Here, culti- 

 vation shows itself as having played an important 

 part. Let us consider, for instance, the cabbage, 

 Brassica oleracea, which is most probably a European 

 species. While Theophrastus recognised three varie- 

 ties, Pliny was acquainted with six, Tournefort with 

 twenty, and De Candolle enumerates more than thirty. 

 These varieties are probably all due to cultivation, and 

 in some cases the differences between them are very 

 considerable, and the differences between the varieties 

 and the parent form, which still exists in France and 

 England, are greater still. Almost every part has 

 varied in this species, from the root to the tip of the 

 leaves and the peduncles of the flowers. Compare 

 Brussels sprouts and Hungarian turnips, cauliflowers 

 and common cabbage, for instance, or let us turn 

 to the common kidney bean (Phaseolus vulgaris) ; 

 here also varieties are numerous. The potato has 

 also a large number of varieties although its cultiva- 



N 



