CLOSE AMD CROSS FEKTILIZATION CONTKASTED. 4-19 



IpOM(EA puepcrea. 



" 1153. The results of close and cross fertilization, as shown by 

 the weight of the seed-capsules, are given by Darwin thus : " The 

 offspring of intercrossed plants of the ninth generation, crossed 

 by a fresh stock, compared with plants of tlie same stock inter- 

 crossed during ten generations, both sets of plants left uncovered 

 and naturally fertilized, produced capsules by weight as 100 

 to 61." 1 



1 The following summary (Darwin : Effects of Cross and Self Fertilization, 

 p. 56) shows more of the results : — 



First generation of crossed mid self-fertilized plants growing in covtpetition 

 with one another. Sixty-five capsules produced from flowers on five crossed 

 plants fertilized hy pollen from a distinct plant, and fifty-five capsules pro- 

 duced from flowers on five self-fertilized plants, fertilized by their own pollen, 

 contained seeds in the proportion of 100 to 93. 



Fifty-six spontaneously self-fertilized capsules on the above five crossed 

 plants, and twenty-Bve spontaneously self-fertilized capsules on the above five 

 self- fertilized plants, yielded seeds in the proportion of . . . 100 to 99. 



Combining the total number of capsules produced by these plants and the 

 average number of seeds in each, the above crossed and self-fertilized plants 

 yielded seeds in the proportion of 100 to 64. 



Other plants of this generation grown under unfavorable conditions and 

 spontaneously self-fertilized yielded seeds in the proportion of . 100 to 45. 



2P 



