PLANT BREEDING AND EVOLUTION 



177 



unusual rate and conquered for a time the opposed crossed plants ; 

 and two exceptions in the ninth generation, though one of these 

 plants only equaled its crossed opponent. Therefore, of the seventy- 

 three crossed plants sixty-eight grew to a greater height than the 

 self-fertilized plants to which they were opposed. 



Lupine. When the seedlings were only four inches in height, the 

 crossed plants had a slight advantage over their opponents. When 

 grown to their full height, every one of the crossed plants exceeded 

 its opponent in height. Nevertheless, the self-fertilized plants in 

 all three pots flowered before the crossed. The measurements are 

 given in the following table: 



LUPINUS LUTEUS 



The eight crossed plants here average 30.78 and the eight self- 

 fertilized plants 25.21 inches in height, or as 100 to 82. All of these 

 plants were left uncovered in the greenhouse to set their pods, but 

 they produced very few good ones, perhaps in part owing to few 

 bees visiting them. The crossed plants produced nine pods, contain- 

 ing on an average three seeds, so that the seeds from an equal num- 

 ber of plants were as 100 to 88. 



Garden pea. In 1867 I covered up several plants of the Early 

 Emperor pea, which was not then a very new variety, so that it must 

 already have been propagated by self-fertilization for at least a dozen 

 generations. Some flowers were crossed with pollen from a distinct 

 plant growing in the same row, and others were allowed to fertilize 

 themselves under a net. The two lots of seeds thus obtained were 



