CIIAP. II. CROSSED AND SELF-FERTILISED PLANTS. 33 



100 to 94. Taking into consideration the number of capsules 

 together with the average number of seeds, the crossed plants 

 (spontaneously self-fertilised) produced seeds in comparison with 

 the self-fertilised plants (spontaneously self-fertilised) in the 

 proportion of 100 to 35. By whatever method the fertility of 

 these plants is compared, the crossed are more fertile than the 

 self-fertilised plants. 



I tried in several ways the comparative vigour and powers of 

 growth of the crossed and self-fertilised plants of this third 

 generation. Thus, four self-fertilised seeds which had just 

 germinated were planted on one side of a pot, and after an in- 

 terval of forty-eight hours, four crossed seeds in the same state 

 of germination were planted on the opposite side ; and the pot 

 was kept in the hothouse. I thought that the advantage thus 

 given to the self-fertilised seedlings would have been so great 

 that they would never have been beaten by the crossed ones. 

 They were not beaten until all had grown to a height of 18 

 inches; and the degree to which they were finally beaten is 

 shown in the following table (No. IV.). We here see that the 

 average height of the four crossed plants is 76 ' 62, and of the 

 four self-fertilised plants 65 '87 inches, or as 100 to 86 ; there- 

 fore less than when both sides started fair. 



TABLE IV. (Third Generation, the self-fertilised Plants having 

 had a start of forty-eight hours.") 



Crossed and self-fertilised seeds of the third generation were 

 also sown out of doors late in the summer, and therefore under 

 unfavourable conditions, and a single stick was given to each 

 lot of plants to twine up. The two lots were sufficiently 

 separate so as not to interfere with each other's growth, and the 

 ground was clear of weeds. As soon as they were killed by the 

 first frost (and there was no difference in their hardiness), the 

 two tallest crossed plants were found to be 24 5 and 22 5 inches. 



