Chap. VIII. FLOWERS ON THE SAME PLANT. 301 



fertilised plants, we find that the mean height of 

 seventy-three such crossed plants, in the course of ten 

 generations, was to that of the same number of 

 self-fertilised plants as 100 to 77 ; and in the case of 

 the plants of the tenth generation in weight as 100 to 

 44. Thus the contrast between the effects of crossing 

 flowers on the same plant, and of crossing flowers on 

 distinct plants, is wonderfully great. 



(3.) Mimulus luteus. Twenty-two plants raised by 

 crossing flowers on the same plant were grown in 

 competition with the same number of self-fertilised 

 plants ; and the former were to the latter in height as 

 100 to 95, or if four dwarfed plants are excluded as 

 100 to 101 ; and in weight as 100 to 103. In seven out 

 of the eight pots a self-fertilised plant flowered before 

 any of the intercrossed. So that here again the self- 

 fertilised exhibit a trifling superiority over the inter- 

 crossed plants. For the sake of comparison, I may 

 add that seedlings raised during three generations 

 from a cross between distinct plants were to the self- 

 fertilised plants in height as 100 to Go. 



(4.) Pelargonium zonale. Two plants growing in 

 separate pots, which had been propagated by cuttings 

 from the same plant, and therefore formed in fact 

 parts of the same individual, were intercrossed, and 

 other flowers on one of these plants were self-fertilised ; 

 but the seedlings obtained by the two processes did 

 not differ in height. When, on the other hand, flowers 

 on one of the above plants were crossed with pollen 

 taken from a distinct seedling, and other flowers were 

 self-fertilised, the crossed offspring thus obtained were 

 to the self-fertilised in height as 100 to 74. 



(5.) Origanum vulgare. A plant which had been 

 long cultivated in my kitchen garden, had spread by 

 stolons so as to form a large bed or clump. Seedlino-s 



