Helianthiis Annuus Syncotyleiis. 469 



generation ; on the other it shows that this can sometimes 

 be passed over, inasmuch as in a fortunate case the high 

 value of 80-907o may be directly attained; notwithstand- 

 ing that this never appeared until after the 55% stage 

 had been reached in the species dealt with in that table. 

 When I repeated the experiment described for my tri- 

 cotylous race of Helichrysiun bracteatum, I had to pass 

 through several generations before reaching the hereditary 

 value of about 50%, and this also shows that in different 

 cases the same value may be reached by means of dif- 

 ferent numbers of generations. We may therefore con- 

 clude that the isolation of a syncotylous race takes place 

 according to the same scheme as that wdiich has been 

 found for the tricotylous intermediate races. 



The general statements on page 17 of this volume 

 and elsewhere relating to the isolation of eversporting 

 varieties, and the apparent increase in variability, by 

 which we explained the isolation of the five-leaved red 

 clover, find an experimental confirmation in the present 

 instance. The new race departs rapidly from the type 

 of its species, but only because it is approaching its own 

 new type. 



Into the group of figures given on the preceding 

 page I have inserted a value for 1889 relating to the 

 first-mentioned line of my race. It would take me too 

 long to describe the subsequent generations singly, but, 

 as is very important in the culture of such forms, they 

 were treated in the same wav ever vear. I shall there- 

 fore give the pedigree of the wdiole culture on the fol- 

 lowing page. 



In this summary I have written at the top the per- 

 centage number of syncotyls in the crops in such a way 

 that the single numbers have been associated into small 



