REPRODUCTION IN PLANTS 83 



turned out of their pots and planted in the open ground, so as to 

 form five separate clumps. Early in the following summer (1869) 

 they flowered profusely, and' being visited by humble-bees set 

 many capsules which were carefully collected from all the plants 

 on both sides. The crossed plants produced 167 capsules, and the 

 self-fertilized only 17 ; or as 100 to 10. So that the crossed plants 

 were more than twice the height of the self-fertilized, generally 

 flowered first, and produced ten times as many naturally fertilized 

 capsules. 



"By the early part of the summer of 1870 the crossed plants in 

 all the five clumps had grown and spread so much more than the 

 self-fertilized, that any comparison between them was superfluous. 

 The crossed plants were covered with a sheet of bloom, whilst only 

 a single self-fertilized plant, which was much finer than any of its 

 brethren, flowered. The crossed and self-fertilized plants had now 

 grown all matted together on the respective sides of the superficial 

 partitions still separating them ; and in the clump which included 

 the finest self-fertilized plant, I estimated that the surface covered 

 by the crossed plants was about nine times as large as that covered 

 by the self-fertilized plants. . . . 



"The ensuing winter was very severe, and in the following spring 

 (1871) the plants were again examined. All the self-fertilized 

 were now dead, with the exception of a single branch on one plant, 

 which bore on its summit a minute rosette of leaves about as large 

 as a pea. On the other hand, all the crossed plants without excep- 

 tion were growing vigorously. So that the self -fertilized plants, 

 besides their inferiority in other respects, were more tender. 



"Another experiment was now tried for the sake of ascertaining 

 how far the superiority of the crossed plants, or to speak more cor- 

 rectly, the inferiority of the self-fertilized plants, would be trans- 

 mitted to their offspring. The one crossed and one self-fertilized 

 plant, which were first raised, had been turned out of their pot and 

 planted in the open ground. Both produced an abundance of very 

 fine capsules, from which fact we may safely conclude that they had 

 been cross-fertilized by insects. Seeds from both, after germinating 

 on sand, were planted in pairs on the opposite sides of three pots. 



