176 EXPERIMENTAL EVOLUTION LECT. 



says, "we should have believed a priori &&&. a much 

 larger number of species which have been cultivated for 

 more than 4,000 years, would have departed from the 

 original type to such a degree that the latter could not 

 be recognised. It appears, on the contrary, that the 

 wild forms have generally persisted." And he goes 

 on to explain this fact in two ways. First of all, the 

 period of 4,000 years is comparatively short, when we 

 consider the duration of most phanerogamous species ; 

 and on the other hand, intercrossing between the 

 wild and the cultivated forms may have prevented 

 the production of considerable differences between 

 them in all cases where the wild form persisted. This 

 last view is very important and goes far to explain 

 why the cases where the wild progenitor is not re- 

 cognisable are not more frequent ; and if it is correct, 

 we should find the largest departure from the original 



X. Species not found in a wild or sub-spcitaneous condition, 

 having originated in countries whose indigenous flora is 

 yet incompletely known, but more different from the wild 



species of these countries than in the preceding case 18 



Amorphophallus konjak, Aracacha esculenta, Brassica 

 chinensis, Capsicum annuum, Chenopodium quinoa, Citrus 

 nobilis, Cucurbita ficifolia, Dioscorea alata, Dioscorea 

 batatas, Dioscorea sativa, Eleusine coracana, Lucuma 

 mammosa, Nephelium Litchi, Pisum sativum*, Saccharum 

 orncinarum, Sechium edule, Trichosanthes anguina*, Zea 



Total 247 



