16 The Significance of Horticultural Varieties. 



useless and indifferent anomalies are common enough, 

 especially in extensive cultures. 



When a new horticultural variety has been isolated 

 and "fixed," that is to say improved and rid of impuri- 

 ties by a few years' cultivation no considerable further 

 improvement in the same direction is to be expected. 

 Only two ways of progress are still at hand. These are 

 to wait for the chance appearance of a new abnormality 

 in the same strain, or to combine the new character with 

 others by crossing. The former method is dependent 

 on chance and therefore often unsatisfactorv. The sec- 

 end is almost sure to succeed, and thus it is always chosen. 

 Each new character is immediately transferred to nu- 

 merous other varieties of the species and a corresponding 

 number of novelties obtained in this way. Thus Le- 

 MOiNE transferred the double flowers of a single douljle 

 lilac to several dozen varieties, and the Cactus Dahlia 

 was, very soon after its introduction, obtainable in almost 

 every shade of color and doubleness. Ordinarily this 

 process is described in the opposite way — that is to say, 

 it is claimed that the properties of the old varieties are 

 transferred to the new type. In this way there appears 

 a vast series of varieties forming a new group co-exten- 

 sive with the older forms of the original species. Thus 

 a single new character can double the number of varieties. 

 Petunias, Zinnias and Fuchsias are familiar examples of 

 the application of this method in former times. Gladiolus, 

 Begonia and many others of its recent application. The 

 ostrich-feather Chrysanthemum (with ciliated petals) 

 arose about thirty years ago in a single varietv (Alph. 

 Hardy), but can now be obtained in large numbers of 

 forms. 



The doctrine of the onesided increase of variability 



