VIII WILD AND DOMESTIC VARIETIES yy 



would be a simple though perhaps tedious task to 

 denote all the different varieties by a series of letters 

 indicating the factors which they contain, 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. PI. II., 7) suddenly 

 turned up in such a family as that shown on Plate 

 IV., we should be able to get a hooded form corre- 

 sponding to each of the forms with the erect stan- 

 dard ; in other words, the arrival of the new form 

 would give us the possibility of fourteen varieties 

 instead of seven. As we know, the hooded char- 

 acter already exists. It is recessive to the erect 

 standard, and we have reason to suppose that it 

 arose as a sudden sport by the omission of the factor 

 in whose presence the standard assumes the erect 

 shape characteristic of the wild flower. It is largely 

 by keeping his eyes open and seizing upon such 

 sports for crossing purposes that the horticulturist 

 " improves " the plants with which he deals. How 

 these sports or mutations come about we can 

 now surmise. They must owe their origin to a 

 disturbance in the processes of cell division through 

 which the gametes originate. At some stage or 



