284 SUMMARY OF MEASUREMENTS. CHAP. VIL 



column, that of the crossed plants being taken as 

 100. A few other cases have already been recorded 

 in Table C in reference to plants crossed by a fresh 

 stock. I regret that more trials of this kind were not 

 made, as the evidence of the superiority of the crossed 

 over the self-fertilised plants is thus shown in a more 

 conclusive manner than by their relative heights. But 

 this plan was not thought of until a rather late period, 

 and there were difficulties in the way, as the seeds 

 had to be collected when ripe, by which time the plants 

 had often begun to wither. In only one out of the 

 eleven cases in Table B, that of Eschscholtzia, do the 

 self-fertilised plants exceed the crossed in weight ; and 

 we have already seen they are likewise superior to them 

 in height, though inferior in fertility, the whole ad- 

 vantage of a cross being here confined to the repro- 

 ductive system. With Vandellia the crossed plants 

 were a little heavier, as they were also a little taller 

 than the self-fertilised ; but as a greater number of 

 more productive capsules, were produced by the cleis- 

 togamic flowers on the self-fertilised plants than by 

 those on the crossed plants, the case must be left, as 

 remarked under Table A, altogether doubtful. The 

 crossed and self-fertilised offspring from a partially 

 self-sterile plant of Reseda odorata were almost equal 

 in weight, though not in height. In the remaining 

 eight cases, the crossed plants show a wonderful 

 superiority over the self-fertilised, being more than 

 double their weight, except in one case, and here 

 the ratio is as high as 100 to 67. The results thus 

 deduced from the weights of the plants confirm in a 

 striking manner the former evidence of the beneficial 

 effects of a cross between two plants of the same stock ; 

 and in the few cases in which plants derived from a 

 cross with a fresh stock were weighed, the results are 

 similar or eveu more striking. 



