380 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



48 per cent and 51 per cent. In the F2 and F3 there was a more 

 general and graded distribution between the extremes, but in 

 the F3 two plants exhibited a percentage of 56 and 70, the latter 

 being a decided advance over any plant of previous generations. 

 Considering the three generations together, the frequency curve 

 becomes more regularly skew with large numbers of individuals 

 in the self-sterile class and fewer numbers in the successive classes 

 leading to higher self-fertility. While the average percentage of 

 the F3 is not higher than that of the F2, there are certain plants 

 with decidedly increased self-fertility. 



A further point of considerable significance in respect to the 

 heredity of self-fertility pertains to the relative behavior of families 

 derived from parents which had decidedly different degrees of 

 self-fertility. Progenies of the two plants of the Fi showing high 

 self-fertility were grown. Of 18 descendants of {E3 X A) no. 4, 

 only 10 were self-fertile with an average percentage of 26; for the 

 9 for which data were secured i plant showed a fertility of 50 per 

 cent and another of 43 per cent. From {E22 X A) no. 10, in an 

 F2 generation of 23 plants only 1 1 were self-fertile with an average 

 percentage of 19.7 and with no plant as strongly self-fertile as the 

 parent. The F3 progenies continued from 5 of the F2 plants of 

 this family, as summarized in table 6, gave rather irregular results, 

 but with the average of each series decidedly lower than that of 

 the grandparent. The total averages are 20.1 per cent for the 

 self-fertile plants, and 9.3 per cent for all plants, which is only 

 slightly above that for the entire Fi, Fo, and F3 populations. 



In comparison with these, the progenies of plants exhibiting low 

 self-fertility showed no appreciable differences in fertility. For 

 example, the progeny of {A X E22) no. 2, a plant only 6 per cent 

 self-fertile, gave 9 self-fertile plants out of 19 with an average 

 percentage of 24 and a range extending to 52 per cent. Likewise 

 the F2 from {A X E22) no. 4 showed an average fertility of 14. i 

 per cent and the F3 an average of 18.5 per cent with the total 

 average quite like that of families derived from parents highly 

 fertile. 



Offspring from F2 plants, either highly or feebly self-fertile, 

 behave quite similarily and regress in marked manner toward the 

 average of the F2 generation. The higher averages for in(li\iduals 

 or for lines of progeny occur without direct relation to the per- 

 centage fertility of the immcfliate parentage. 



