258 SUMMARY OF MEASUREMENTS. CHAP. VII. 



seedlings were grown in competition with one another, 

 and differed greatly in height and fertility. For the 

 offspring from the cross with a fresh stock exceeded in 

 height the intercrossed plants in the ratio of 100 to 78 ; 

 and this is nearly the same excess which the inter- 

 crossed had over- the self-fertilised plants in all ten 

 generations taken together, namely, as 100 to 77. The 

 plants raised from the cross with a fresh stock were 

 also greatly superior in fertility to the intercrossed, 

 namely, in the ratio .of 100 to 51, as judged by the 

 relative weight of the seed-capsules produced by an 

 equal number of plants of the two sets, both having 

 been left to be naturally fertilised. It should be 

 especially observed that none of the plants of either lot 

 were the product of self-fertilisation. On the contrary, 

 the intercrossed plants had certainly been crossed for the 

 last ten generations and probably during all previous 

 generations, as we may infer from the structure of the 

 flowers and from the frequency of the visits of humble- 

 bees. And so it will have been with the parent-plants 

 of the fresh stock. The whole great difference in height 

 and fertility between the two lots must be attributed to 

 the one being the product of a cross with pollen from a 

 fresh stock, and the other of a cross between plants of 

 the same old stock. 



This species offers another interesting case. In the 

 five first generations in which intercrossed and self- 

 fertilised plants were put into competition with one 

 another, every single intercrossed plant beat its self- 

 fertilised antagonist, except in one instance, in w 

 they were equal in height. But in the sixth gen 

 ration a plant appeared, named by me the Hero, 

 markable for its tallness and increased self-fertility, 

 and which transmitted its characters to the next th 

 generations. The children of Hero were again self- 



