104 Expeinments ivith Primula sinensis 



is due. If the former suggestion should prove to be correct, the fact 

 that all our fully coloured races, when crossed with " Snowdrift," have 

 given pale colours in F., ; and the further fact that two heterozygous 

 "Sirdars" have thrown only "Sirdars" and whites, would be merely 

 fortuitous results depending on the particular races which have been 

 used. It may be noted that, if the pale colours are an independent 

 series, certain matings between ^2 " Sirdars " and pale pinks should 

 give full colours, while others should not do so ; the alternative case 

 would seem to imply that all these matings should give full colours. 



The primary colour of the fully coloured flower is red'. The 

 numerous shades of red are due to the presence or absence of factors 

 which reduce the intensity of the pigmentation, and other factors which 

 produce slight changes of tint. In the simplest cases the magenta 

 class may be regarded as due to the action of a factor epistatic to the 

 factors which give rise to the red colour ; in other cases, however, 

 the proportions of the magenta and the more rosj' class indicate the 

 9 : 7 ratio (see under " Rosy Magenta," p. 110) ; and in yet another case 

 an intermediate, mated with a clean red, gave typical magentas among 

 its offspring. There exist corresponding shades of magenta for many, 

 if not all, the numerous shades of red. 



The flaked or splashed forms of coloured flowers show a considerable 

 range of variation in the degree to which the flaking is developed, and 

 in the size and form of the coloureil areas. The distinction between 

 the red and magenta colours in flakes is often attended with some 

 difficulty. In self-coloured red flowers it will often be noticed that 

 a bluer tint is developed at the edges of the petals, and in forms in 

 which the colour is weakly developed just round the eye a similar 

 bluish tint will be noticed in this region. In the same way, there 

 seems to be a tendency for the red colour to pass into a bluer tint at 

 the edges of the coloured stripes and splashes, and in flowers showing 

 fine as well as coarse splashes, it is often to be noticed that the coarse 

 splashes are red, while the minute dots of colour, viewed with the naked 

 eye, would certainly be put down as magenta-. My experience of flaked 

 flowers is limited to the F^s of crosses in which the "Ivy-leaf" took 



• The relations of blue to the other colours have not been worked out. The fact that 

 blues appeared in small numbers in a cross in which the rest of the coloured offspring 

 were red suggests that blue is either hypostatic to red, or, if it forms an independent 

 series, is masked by red. 



- A somewhat similar difficulty occurs in the " Sirdar " type, owing to the optical 

 effect of the intermingled coloured and colourless dots. In this case, however, the distinction 

 between magentas and reds can be made readily with the help of a microscope. 



