212 



lock: 



I— COLOUR OF POLLEN. 



Bliieness of the pollen appears to behave as a Mendelian 

 dominant to the absence of blue (white or faintly grayish 

 pollen). The heterozygote is, however, invariably of a distinctly 

 paler blue colour than the homozygote. The evidence for 

 this statement regarding Mendelian behaviour appears in 

 Table III. 



Table III. 



Langsdo7fii Crosses Pollen Colour. 



In every case where a variety of N. langsdorfii was crossed 

 with a species or variety in which the pollen was white, the 

 blue colour appeared, more or less diluted, m the pollen of all 

 the F 1 plants. In F 2 there was sliarp segregation into whites 

 and blues. In some cases a notable distinction could be drawn 

 between the shades of blue shown by the pollen of different 

 F 2 plants, some being nearly as dark as the original N. langs- 

 dorfii pollen, and others again being more like the primary 



