G. P. HECTOR 173 
the few exceptions noted, are associated with colourless ligules, but not vice 
versa. 
The actual numbers observed in 4 families were as follows :-— 
27 AB : 9 Ab : 28 ab 
Observed 1,226 at : 414 : 1,267 (4 families of 
2,907 plants) 
aS 
Coloured grain—white grain : White grains : Coloured grains—white grains 
1,220 6 414 951 316 
27ABC 9ABe 9AbC,9aBC,3abC 3Abce, 3aBe, labe 
SSS = CoCo 
Expect 1226°37 408-79 953°85 317:95 
It thus appears that the factor responsible for colour in the grain is the 
third or C factor responsible for colour in the ligule. When C is present, the 
grain is coloured (with the six exceptions noted) ; when C is absent, the grain 
is white. Thus the colour in the grain must be due to this factor C, or to a 
factor completely linked with it. In this connection, the six exceptions with 
coloured ligules and white grains, are important, as furnishing further evidence 
in support of the latter view, for if one and the same factor is responsible for 
both ligule and grain, it is difficult to conceive by what mechanism these 
exceptions could come about. On the other hand, if two linked factors are 
responsible, then these exceptions are simply rare instances of breaks in the 
linkage, such as have already been noted above in the case of the colour patterns 
in the vegetative parts, in which some of the constituent parts have been 
seen occasionally to break away. 
2. The second exceptional case has been found in the cross C9 x ©,25. 
Here the parent C9 had a dark red grain, C25 a white. On crossing, the F, 
was like the C9 grain but paler, and in F,, segregated into four types of grain, 
dark red, pale red, pale amber and pure white. The figures obtained in 3 
families examined are given in the table— 
Dark red Pale red Pale amber White 
1 ale 69 150 15 40 
2 ss 48 119 34 25 
3 dc 67 87 36 25 
ToTAL 184 356 85 ra) 
Se eee 
177 
