CHAPTER XXX 

 VARIATION AND ITS RESULTS 



370. THE FACT OF VARIATION. No two plants are 

 alike (16). In size, form, color, weight, vigor, produc- 

 tiveness, season, or other characters, they differ. The 

 most usual form of any plant is considered to be its 

 type, that is, its representative form. Any marked de- 

 parture from this type is a variation, that is, a difference. 



371. THE KINDS OF VARIATIONS. Variations are of 

 many degrees. The differences, in any case, may be so 

 slight as to pass unnoticed, or they may be so marked as 

 to challenge even the casual observer. If a red -flowered 

 plant were to produce flowers in different shades of red, 

 the variation might not attract attention ; but if it were 

 to produce white flowers, the variation would be marked. 

 Whenever the variation is so marked and so constant as 

 to be worth naming and describing, it is called a variety 

 in descriptive botany. If the variation is of such charac- 

 ter as to have value for cultivation, it is called an agri- 

 cultural or horticultural variety. There is no natural 

 line of demarcation between those variations which chance 

 to be named and described as varieties and those which do 

 not. Varieties are only named variations. 



372. Variations may arise in three ways: (1) directly 

 from seeds; (2) directly from buds; (3) by a slow 

 change of the entire plant after it has begun to grow. 



373. Variations arising from seeds are seed- variations ; 

 those which chance to be named and described are seed- 

 varieties. Never does a seed exactly reproduce its parent: 

 if it did, there would be two plants alike. Neither do any 



^228) 



