io8 



BOTANICAL GAZETTE 



[fEBRI'ARY 



two things, namely, the fact that Mendel's law was not discovered 



economic 



quarters the notion prevails that Mendelian inheritance is a function 

 only of self-fertilizing or inbred strains. 



Fig. 3. — Curves showing the extent of branching in three families of "Russian 

 sunflower; the dotted line at left represents the offspring of two xmbranched parents; 

 the dotted line at the center represents the offspring of two branched parents, one of 

 which must have been an extracted dominant; the unbroken line shows the condition 

 of a family from the mother <rf the pure unbranched family, but with pollination 

 unguarded; the dominance of branching produces a branched offspring in each case 

 that successful fertilization took place by means of pollen from a branched plant. 



The foregoing account of experiments on the inheritance of the 

 branching habit in Helianihus annuiis may be recapitulated in the 

 form of a familv tree thus : 



Branched (Dll)xrnbranched (R) 



I 

 28 B (BR) 



H 



( 



54B(DD-4-DR4-RR- 

 68B DD-^DR-fRR, 



6qB DDorDR) } 

 i^B DDorDR) ) 



1 

 2U iRR 



2 U iRR 



\ 

 31 U (RR 



6 RR) 

 More or less branched 



22 U RR 



