324 



FEETILITY OF CROSSED 



CHAP. IX. 



A second table, G-, gives the relative fertility of 

 flowers on crossed plants again cross-fertilised, and of 

 flowers on self- fertilised plants again self-fertilised, 

 either in the first or in a later generation. Here two 

 causes combine to diminish the fertility of the self- 

 fertilised flowers ; namely, the lesser efficacy of pollen 

 from the same flower, and the innate lessened fertility 

 of plants derived from self-fertilised seeds, which as we 

 have seen in the previous Table D is strongly marked. 

 The fertility was determined in the same manner as 

 in Table F, that is, by the average number of seeds per 

 capsule ; and the same remarks as before, with respect 

 to the different proportion of flowers which set capsules 

 when they are cross-fertilised and self-fertilised, are 

 here likewise applicable. 



TABLE G Relative Fertility of Flowers on Crossed and Self- 

 fertilised Plants of the First or some succeeding Generation ; the 

 former being again fertilised with Pollen from a distinct Plant, 

 and the latter again with their own Pollen. Fertility judged 

 of by the average Number of Seeds per Capsule. Fertility of 

 Crossed Flowers taken as 100. 



IPOMCEA PURPUEEA crossed and self-fertilised flowers on 

 the crossed and self-fertilised plants of the 1st generation 

 yielded seeds as 



IPOMCEA PURPUKEA crossed and self-fertilised flowers on 

 the crossed and self-fertilised plants of the 3rd generation 

 yielded seeds as 



IPOMCEA PURPUREA crossed and self-fertilised flowers on 

 the crossed and self-fertilised pi ints of the 4th generation 

 yielded seeds as 



IPOMCEA PURPUREA crossed and self-fertilised flowers on 

 the crossed and self-fertilised plants of the 5th generation 

 yielded seeds as ) 



MIMULUS LUTEUS crossed and self-fertilised flowers on the 

 crossed and self-fertilised plants of the 3rd generation 

 yielded seeds as (by weight) 



MIMULUS LUTEUS same plants treated in the same manner 

 on following year yielded seeds as (by weight) . . 



MIKULUS LUTEUS crossed and self-fertilised flowers on the 

 crossed and self-fertilised plants of the 4th generation 

 yielded seeds as (by \v tight) 



100 to 93 



107 



40 





