70 MIMULUS LUTE US. CHAP. III. 



carefully. The self-fertilised seedlings came up rather before the 

 crossed, but both bts were for a time of equal height. When first 

 measured, the average height of the six tallest crossed plants in 

 the three pots was 7 '02, and that of the six tallest self-fertilised 

 plants 8'97 inches, or as 100 to 128. When fully grown the 

 same plants were again measured, with the result shown in the 

 following table : 



TABLE XVIII. (Seventh Generation.) 



The average height of the six crossed is here 11 '43, and that 

 of the six self-fertilised 15-64, or as 100 to 137. 



As it was now evident that the tall white variety transmitted 

 its characters faithfully, and as the self-fertilised plants consisted 

 exclusively of this variety, it was manifest that they would 

 always exceed in height the crossed plants which belonged 

 chiefly to the original shorter varieties. This line of experiment 

 was therefore discontinued, and I tried whether intercrossing 

 two self-fertilised plants of the sixth generation, growing in dis- 

 tinct pots, would give their offspring any advantage over the 

 offspring of flowers on one of the same plants fertilised with then- 

 own pollen. These latter seedlings formed the seventh genera- 

 tion of self-fertilised plants, like those in the right-hand column 

 in Table XVIII. ; the crossed plants were the product of six 

 previous self-fertilised generations with an intercross in the 

 last generation. The seeds were allowed to germinate on sand, 

 and were planted in pairs on opposite sides of four pots, all the 

 remaining seeds being sown crowded on opposite sides of Pot 

 V. in Table XIX. ; the three tallest on each side in this latter pot 

 being alone measured. All the plants were twice measured the 

 first time whilst young, and the average height of the crossed plants 



