16 DAEWINISII STATED BY DARWIN HIMSELF. 



quite barren, except under sucli favorable conditions. 

 The season of 1864 was unfaTorable. In 1863 the female 

 A produced "some fruit" ; in 1864 only nine ; and in 

 1865 ninety-seven fruit. The female B in 1863 was 

 "covered with fruit"; in 1864 it bore twenty-eight; 

 and in 1865 "innumerable very fine fruits." I may add 

 that three other female trees growing close by were ob- 

 served, but only during 1863, and they then bore abun- 

 dantly. With respect to the poUeniferous bushes, the one 

 marked C did not bear a single fruit during the years 

 1863 and 1864, but during 1865 it produced no less than 

 ninety-two fruit, which, however, were very poor. I se- 

 lected one of the finest branches with fifteen fruit, and 

 these contained twenty seeds, or on an average 1 "33 per 

 fruit. I then took by hazard fifteen fruit from an ad- 

 joining female bush, and these contained forty-three 

 seeds ; that is, more than twice as many, or on an aver- 

 age 3 '8 6 per fi'uit. Many of the fruits from the female 

 bushes included four seeds, and only one had a single 

 seed ; whereas, not one fruit from the poUeniferous 

 bushes contained four seeds. Moreover, when the two 

 lots of seeds were compared, it was manifest that those 

 from the female bushes were the larger. The second 

 poUeniferous bush, D, bore in 1863 about two dozen 

 fruit, in 1864 only three very poor fruit, each containing 

 a single seed ; and in 1865, twenty equally poor fruit. 

 Lastly, the three poUeniferous bushes, E, F, and Gr, did 

 not produce a single fruit during the three years 1863, 

 1864, and 1865. 



EFFECT OF CLIMATE OIT REPEODUCTION. 



Page 293. ^ tendency to the separation of the sexes 



in the cultivated strawberry seems to be much 



more strongly marked in the United States than in Eu- 



