SPECIES CROSSES IN THE GENUS NICOTIANA. 



213 



hybrid in this respect. No case was observed of the appear- 

 ance of blue pollen in the offspring of plants with white 

 pollen only. 



n.— COLOUR OF THE COROLLA. 



Here again, so far as the evidence goes, it would appear as 

 if the presence of a yellow pigment in the corolla were a simple 

 dominant to tlie absence of this colour. But the shade of 

 yellow shou-n by the heterozygote is distinctly paler than that 

 of the homozygote. 



It may be noted here that the phenomena of colour inherit- 

 ance seen in the offspring of crosses between N. forgetiana 

 and other species appear to be complex. A whole series of 

 reds and purples segregates out in F 2. So far a sufficient 

 number of plants have not been grown to establish any definite 

 numerical relationsliip between the various shades. 



Table IV, relates simply to the inlieritance of the yellow 

 colour derived from X. langsdorfii. 



Table IV. 



Langsdorfii Grosses Corolla Colour. 



* I.e., no yellow pigment, purple pigment was present, 

 t Some f'ontaincd pvii-ple pigment. 



