viii WILD AND DOMESTIC VARIETIES 83 



light wing (L) was dropped out in certain plants. In 

 1860 we have evidence that the pale purple or Pico tee, 

 and with it doubtless the Tinged White, had come into 

 existence. This time it was the factor for intense colour 

 which had dropped out. And so the story goes on until 

 the present day, and it is now possible to express by the 

 same simple method the relation of the modern shades, 

 of purple and reds, of blues and pinks, of hooded and 

 wavy standards, to one another and to the original wild 

 form. The constitution of many of these has now been 

 worked out, and to-day it would be a simple though per- 

 haps tedious task to denote all the different varieties by 

 a series of letters indicating the factors which they con- 

 tain, instead of by the present system of calling them 

 after kings and queens, and famous generals, and ladies 

 more or less well known. 



From what we know of the history of the various strains 

 of sweet peas one thing stands out clearly. The new 

 character does not arise from a pre-existing variety by 

 any process of gradual selection, conscious or otherwise. 

 It turns up suddenly complete in itself, and thereafter 

 it can be associated by crossing with other existing 

 characters to produce a gamut of new varieties. If, for 

 example, the character of hooding in the standard (cf. 

 PL II., 7) suddenly turned up in such a family as that 

 shown on Plate IV. we should be able to get a hooded 

 form corresponding to each of the forms with the erect 



