1922] 



Setchell-Goodspeed-Clausen: Nicotiana Tdbacum 



503 



In the subsequent generations the behavior was, however, more 

 definite. ISF^HigPosPuPg was grown from a tall F3 plant. No defi- 

 nite notes were taken as to height, but the population was noted as 

 varying. In Fg and subsequent generations the line bred true to tall. 

 ISF^HjsPo-iPiiPia was grown from a short Fg plant. The ninety-seven 

 plants were all of low stature and in subsequent generations the line 

 bred true for low stature. I3F4H20P26P5P8 was grown from a tall 

 F3 plant. Ninety-four plants, although variable in height, all be- 

 longed in the tall class and in subsequent generations the line bred 

 true for tall stature. Nothing but a careful biometrical study under 



TABLE 17 



Fs BEHAVIOR OF SHORT SEGREGANTS. 



well controlled cultural conditions, however, would yield results capa- 

 ble of strict Mendelian analysis. However, it can be said that none 

 of the results here recorded preclude the possibility of such an analysis, 

 although it evidently can not be done in any simple qualitative manner. 



As respects leaf width it was found impossible to make even such 

 a rough classification as was attempted in the case of stature. Here 

 again nothing short of a strict biometrical analysis would furnish the 

 basis for a Mendelian formulation. 



As has been indicated above, three separate lines of this series 

 were carried out to the seventh hybrid generation. Of these, one was 

 a recombination of cliaracters from both parents exhibiting the tall 

 stature and normal flower of virginica with tlie red flower color of 

 calycina. One exhibited a stature intermediate between that of caly- 

 cina and virginica in combination witli llie normal flower shape of 



