SCIENTIFIC COMMITTEE, MAY 15. 



Ixxiii 



The following table shows the various results occurring in the crosses. 

 The first distinction to be drawn is between whites bearing the dark-axil 

 character — call it (D), or its absence (d). By crossing with a coloured 

 flower light-axil variety the point can be settled, for the (D) white will 

 then give a dark-axil cross-bred, whereas the (d) white gives a light-axil 

 cross-bred thus : — 



Coloured tiower x white (D) 

 (tl) 



I 



F, coloured flower, dark axil 



Coloured flower x white (d) 

 (d) ^ 



F, coloured flower, light axil 



Coloured flower x white (D) 

 dark axil 



I 



F, coloured flowers, dark axil 



F., 3 coloured flowers : 1 white 



all dark axil light axil (D) 



Coloured flower x white (d) 

 dark axil 



Fj coloured flowers, dark axil 



Fo 9 coloured flowers 3 coloured flowers 4 white 

 dark axil light axil 



These four white are all alike in appearance, but are really 



1 D D (pure to dark axil) : D d (crosses 

 between dark and light axil) : 1 d d 

 (pure to light axil). 



Excepting in rare and doubtful cases, white-flowered plants have light 

 axils, but they may possess the factor which gives dark axils if it meets 

 flower-colour. There are thus two kinds of white-flowered plants : — 



A. White-flowered bearing D, the dark-axil factor. 



B. White-flowered without D. 



Both A and B have light axils in fact, and to the eye, but if A be 

 crossed with a coloured- flowered, light-axil variety, Fj will be coloured - 

 flowered with dark axils ; while if B be crossed with the same coloured- 

 flowered, light-axil variety, will be coloured-flowered with light axils. 

 In the case where two whites crossed give a coloured Fi this will have 

 dark axil or light axil, according as one or both of the whites bore dark 

 axils or neither. 



If neither bore dark axils this Fi will have light axils, though the 

 flowers are coloured. 



But: 



Then : 



But : 



