LEAKE AND RAM PKA.SAK 131 



It differs from the above in that Type 4, which has a yellow petal, 

 is replaced by Type 9, in which the petal is white. As far as the 

 present discussion is concerned, therefore, the two parents differ in 

 two characters. Type 3 possesses the two dominant factors re- 

 presenting presence of the red and of the yellow colour, which are 

 both absent in Type 9. Type 3, therefore, represents the condition 

 KRYY and Type 9 the condition rryy. Since it is possible to distin- 

 guish the impure form Rr from the pure form RR, it should be 

 possible to recognise in the Fo generation 6 groups which should 

 possess the following numerical proportions : — 



That this expectation is fulfilled is clear from a consideration 

 of Table X, while the close agreement between the expectation 

 and actual results obtained in the subsequent generations, as indi- 

 cated in Tables XI & XIII, leaves no doubt as to the correctness of 

 this interpretation. Plates XVII and XIX illustrate the different 

 forms of petal arising in this cross. 



(3) Type 7 x Type 3. — This cross, as far as the points at 

 present under consideration are concerned, is in all respects similar 

 to the above. In it Type 7 lacks both factors and therefore pos- 

 sesses the constitution rryy, while Type 3, as has already been shown, 

 has the constitution RRYY. The results of the cross, which has 

 been carried as far as the Fg generation, are tabulated in Table XIV 

 from which the agreement is apparent. 



(4) Type 3 x Tij2)e 10.— The doubt as to the exact constitution 

 of Type 10 as regards the petal colour, has already been referred 

 to above (page 126). In the present case the pale yellow condition 



