86 



IPOMCEA PURPUKEA. 



CiiAr. II. 



and that of the sis self-fertilised plants 62 33 inches, or as 100 

 to 75. Every crossed plant exceeded its antagonist in height. 

 In Pot I. the middle plant on the crossed side was slightly 

 injured whilst young by a blow, and was for a time beaten by 

 its opponent, but ultimately recovered the usual superiority. 

 The crossed plants produced spontaneously a vast number more 

 capsules than did the self-fertilised plants ; and the capsules of 

 the former contained on an average 3 - 37 seeds, whilst those of 

 the latter contained only 3 per capsule, or as 100 to 89. But 

 looking only to the artificially fertilised capsules, those on the 

 crossed plants again crossed contained on an average 4 '46 

 seeds, whilst those on the self-fertilised plants again self- 

 fertilised contained 4*77 seeds; so that the self-fertilised cap- 

 sules were the more fertile of the two, and of this unusual fact 

 I can offer no explanation. 



Crossed and self-fertilised Plants of the Sixth Generation. 

 These were raised in the usual manner, with the following result. 

 I should state that there were originally eight plants on each 

 side ; but as two of the self-fertilised became extremely un- 

 healthy and never grew to near their full height, these as well 

 as their opponents have been struck out of the list. If they had 

 been retained, they would have made the average height of the 

 crossed plants unfairly greater than that of the self-fertilised. 

 I have acted in the same manner in a few other instances, when 

 one of a .pair plainly became very unhealthy. 



Table VII. (Sixth Generation.) 



The average height of the six crossed plants is here 87*5, and 

 f the six self-fertilised plan ts 63*16, or as 100 to 72. This large 

 difference was chiefly due to most of the plants, especially the 



