CHAP. VI. CROSSED AND SELF-FERTILISED PLANTS. 209 



The seven crossed plants (for two of them died) here average 

 70 '78 inches, and the nine self-fertilised plants 71 '3 inches in 

 height ; or as 100 to barely 101. In four out of these five pots, 

 a self-fertilised plant flowered before any one of the crossed 

 plants. So that, differently from the last case, the self-fertilised 

 plants are in some respects slightly superior to the crossed. 



If we now consider the crossed and self-fertilised plants of the 

 three generations, we find an extraordinary diversity in their 

 relative heights. In the first generation, the crossed plants were 

 inferior to the self-fertilised as 100 to 178 ; and the flowers on 

 the original parent-plants which were crossed with pollen from a 

 distinct plant yielded much fewer seeds than the self-fertilised 

 flowers, in the proportion of 100 to 150. But it is a strange fact 

 that the self-fertilised plants, which were subjected to very severe 

 competition with the crossed, had on two occasions no advan- 

 tage over them. The inferiority of the crossed plants of this first 

 generation cannot be attributed to the immaturity of the seeds, 

 for I carefully examined them ; nor to the seeds being diseased 

 or in any way injured in some one capsule, for the contents of 

 the ten crossed capsules were mingled together and a few taken 

 by chance for sowing. In the second generation the crossed and 

 self-fertilised plants were nearly equal in height. In the third 

 generation, crossed and self-fertilised seeds were obtained from 

 two plants of the previous generation, and the seedlings raised 

 from them differed remarkably in constitution ; the crossed in the 

 one case exceeded the self- fertilised in height in the ratio of 100 

 to 83, and in the other case were almost equal. This difference 

 between the two lots, raised at the same tune from two plants 

 growing in the same pot, and treated in every respect alike, as 

 well as the extraordinary superiority of the self-fertilised over 

 the crossed plants in the first generation, considered together, 

 make me believe that some individuals of the present species 

 differ to a certain extent from others in their sexual affinities (to 

 use the term employed by Gartner), like closely allied species of 

 the same genus. Consequently if two plants which thus differ 

 are crossed, the seedlings suffer and are beaten by those from 

 the self-fertilised flowers, in which the sexual elements are of 

 the same nature. It is known* that with our domestic animals 



*I have given evidence on mastication,' chap, xviii. 2nd edit, 

 this head in my Variation of vol. ii. p. 146. 

 Animals and Plants under Do- 



