74 MENDELISM CHAP. 



resulted in a complete reversion to the purple colour 

 characteristic of the wild Sicilian form (PI. IV.). In 

 this particular instance subsequent breeding from the 

 purples resulted in the production of six different 

 colour forms in addition to whites. The proportion 

 of the coloured forms to the whites was 9 : 7 

 (cf. p. 41), but it is with the relation of the six 

 coloured forms that we are concerned here. Of 

 these six forms, three were purples and three were 

 reds. The three purple forms were (i) the wild 

 bicolor purple with blue wings known in cultivation 

 as the Purple Invincible (PI. IV., 4) ; (2) a deep 

 purple with purple wings (PI. IV., 5) ; and (3) a very 

 dilute purple known as the Picotee (PI. IV., 6). Cor- 

 responding to these three purple forms were three reds : 



(1) a bicolor red known as Painted Lady (PL IV., 7) ; 



(2) a deep red with red wings known as Miss Hunt 

 (PI. IV., 8) ; and (3) a very pale red which we have 

 termed Tinged White 1 (PL IV., 9). In the F 2 

 generation the total number of purples bore to the 

 total number of reds the ratio 3:1, and this ratio 

 was maintained for each of the corresponding classes. 

 Purple, therefore, is dominant to red, and each of the 

 three classes of red differs from its corresponding 

 purple in not possessing the blue factor (/?) which 

 turns it into purple. Again, the proportion in which 

 the three classes of purples appeared was 9 bicolors, 

 3 deep purples, 4 picotees. We are, therefore, con- 

 cerned here with the operation of two factors : 

 (i) a light wing factor, which renders the bicolor 



1 The reader who searches florists' catalogues for these varieties will 

 probably experience disappointment. The sweet-pea has been much 

 " improved " in the past few years, and it is unlikely that the modern 

 seedsman would list such unfashionable forms. 



