474 



S\'iicof\Ioi(s Races. 



m which the seed-leaves are fused together on both sides 

 (Fig. 90, C and D). Fig. 98 represents such a curve 

 from the harvest of 1889, which includes 2439 seedlings. 

 The absolute numbers of the seedlings which possess the 

 various degrees of symphysis are given below the figure. 

 The groups are obviously arbitrary, but it is not likely 

 that a grouping according to a different scheme would 

 have any essential effect on the form of the curve, for 

 the seedlings with fused peduncles only would always 

 constitute a minimum between the two peaks. 



If we examine the se- 

 ries of figures of our pedi- 

 gree statistically, we see 

 that they are, as a rule, 

 asymmetrical, i. e., the 

 highest values are closer 

 to the one end than to the 

 other. In all the vears 

 with the exception of the 

 first and the last, the high- 

 est peak is shifted in the 

 direction of selection. In 

 order to examine this ef- 

 fect more closely I insti- 

 tuted an experiment in the 

 summer of 1890 on a 

 larger scale alongside the 

 For this purpose I planted 



At. h S. 

 233 20 



I S. ]i K. Vi K. ?4 K. ?io K. 1 K. B. 

 23 57 7.0 J25 226 634. Alnd^ 



Fig. 98. Hclianthiis annuiis syii- 

 cotyleus. Curve representing the 

 degree of syncotyly in the seed- 

 Hngs of the harvest of 1889. At, 

 atavists ; ^ S, iS, peduncles 

 fused along half their extent or 

 entirely; ,^/C 'AK, Y^K, V.,K, 

 I K, seed-leaves fused over 34 of 

 their extent and so forth ; B, 

 pitcher-cotyls or amphicotyls. 



one dealt with on page 470. 

 out about 60 syncotyls from a parent witli a value of 

 81% ; 55 of these gave a sufficient harvest. The values 

 have been arranged in groups in the same way as in the 

 pedigree on page 470, and the sizes of the groups thus 

 obtained, are graphically displayed in Fig. 99 and given 



