IN THE VEGETABLE KINGDOM 51 



about twice as much seed. Cultivated cabbages yielded 

 thrice as many pods by measure as wild cabbages from 

 the rocks of South Wales. The excess of berries produced 

 by the cultivated asparagus in comparison with the wild 

 plants is enormous." l 



Though these plants have been cultivated for a heavy 

 yield of seed under favourable conditions, yet, if these 

 favourable conditions are carried to excess, sterility results. 



" Plants which from any cause grow too luxuriantly 

 and produce leaves, stems, runners, suckers, tubers, bulbs, 

 etc., in excess, sometimes do not flower, or if they flower 

 do not yield seed. To make European vegetables under 

 the hot climate of India yield seed, it is necessary to 

 check their growth, and when one-third grown, they 

 are taken up and their stems and tap-roots cut or 

 mutilated." 



This mutilation being obviously to check nutrition is 

 a conclusive refutation of Darwin's own contention that 

 the luxuriant growth of certain fruits is more probably 

 due to sterility than that sterility is due to luxuriant 

 growth. 



The operation of the principle as a whole is admirably 

 illustrated by the following : " With the varieties of 

 many plants, the adaptation to climate is very close. 

 Thus it has been proved by repeated trials * that few 

 if any of the English varieties of wheat are suitable for 

 Scotland/ but the failure in this case is at first only in 

 the quantity, though ultimately in the quality of the 

 grain produced. The Rev. M. J. Berkely sowed wheat 

 seed from India, and got * the most meagre ears ' on land 

 which certainly have yielded a good crop from English 

 wheat. In these cases varieties have been carried from 



1 Variation of Animal* and Plants under Domestication, chap, xviii. 

 Ibid. 



