214 LOCK : 



Yellow flowered offspring were never seen to originate from 

 white flowered parents. The cross between yellow and white 

 usually showed a corolla of a distinctly paler shade of yellow 

 than that of the yellow parent. Considerable differences in the 

 shades of yellow were to be observed in F 2. 



III.— SHAPE OF THE COROLLA. 



The distinction between a bulged or inflated and a funnel- 

 shaped corolla has ah'eady been mentioned as one of the 

 features separating certain of those varieties of Nicotiana 

 which have been referred more or less provisionally to N. 

 langsdorfii. The two types reappeared among the offspring of 

 several crosses In such cases it seemed to be always possible, 

 with a little trouble, to refer every plant definitely to one class 

 or the other. Individual blossoms might baffle this attempt, 

 but in the case of each plant a typical flower could be chosen, 

 which could be described as either funnel-shaped or bulged. 



There were other considerable differences in the shape of the 

 flowers in addition to this one. But no other feature was 

 observed in respect of which two definite classes could readily 

 be separated. In addition to considerable differences in size, 

 whicli will be dealt with later, there were notable variations 

 in the shape of the lobes of the corolla and in the degree of 

 flatness or hollowness of the limb. But these and other similar 

 characters were not sufficiently easy of definition to permit 

 of any conclusion being arrived at as to whether segregation 

 took place in their case or not. The character breadth of 

 limb divided by length of tube, of which some preliminary 

 measurements were taken, was found to show only a very 

 small variation in the different strains. 



The distinction between funnel-shaped and bulged corollas is 

 shown (with a slight exaggeration) in text figs. 2 and 3. Fig. 1 

 shows the profile of a flower of variety E. The same type 

 reappeared in a few cases in F 2 from crosses in which E 

 represented the pollen parent. The plants which bore flowers 

 of this kind were always dwarfs with crowded inflorescence 

 just like the original specimen. My impression is that this 

 form of flower is to be regarded as the funnel-shaped type 

 modified by association with a second factor. Tlie latter may 



