HOWARD AND HOWAKD. 



"JO 



As mentioned above the fact that the two red factors both pro- 

 duce a red colour makes the identification of these various classes 

 impossible. Nevertheless it was found possible to isolate the two 

 factors. In order to assist in the analysis of the F 2 it was decided 

 to form a set of arbitrary standards by selecting all the tones of red 

 occurring in this generation and to assign all the plants to classes 

 represented by these standards. Twelve definite shades of red were 

 obtained which covered the whole range of tones. In appearance 

 standards 1, 2, 3, w T ere a very pale yellowish red passing by degrees 

 to the full red of 8, 9, 10, 11 and 12. Although grain belonging to 

 standard 1 can always be distinguished with certainty from white 

 grain, nevertheless the colour is so faint that it is more yellow than red 



In classifying the F 2 generation the grain of the twelve stand- 

 ards was placed in watch glasses on white paper in a good north lio-ht 

 and the grains of the remaining F 2 plants were matched singly and 

 their respective places in the series determined. 



The distribution of the F. plants as regards the tone of colour of 

 the red grained individuals is given in the following table and again 

 graphically in Plate I. The red curve is compounded of the three single 

 curves given by three crosses. — 



Cruss. 1 ? 0, of Rg D Standards. 



plants. -___' _____ 



1 2 3 4 5 (J 7 8 9 10 11 15 



Punjab Type 9 

 Fi of all crosses 



Punjab Type 9 x Punjab .~>94 8 21 98 107 91 102 4(i 22 °1 13 -'4 S 

 Type 10. 



Punjab Type 9 x Moz. 705 9 34 _6 ITS 109 70 70 54 °0 L5 13 3 



white. 



P '^ jab „TyP e 9 * Punjab 954 13 27 137 120 184 7S 105 08 96 'JO 42 G 

 Type 2o. 



Total ... 2,253 30 82 321 405 884 250 221 144 137 5(1 79 12 



It will be observed that in the graphic representation the twelve 

 red tones have been assumed for the sake of convenience to differ 

 from one another by an equal amount. This is probably not the 

 case, but does not affect the argument. For all the crosses the 

 numbers have been calculated for 500 plants in order to make the 

 comparison of the curves easier. 



