Horticultural Varieties Arisen Suddenly. 99 



new form are the only argnnients for its sudden appear- 

 ance. 



§ II. HORTICULTURAL VARIETIES WHICH HAVE ARISEN 



SUDDENLY. 



It is a matter of common knowledge that horticultural 

 varieties have very often arisen hy sports. But opinions 

 differ on two points. One is an empirical one and relates 

 to the question of constancy ; the other relates to the 

 meaning of the word variety. The two points are nar- 

 rowdy bound up with one another. If the new form is 

 not constant and pure from seed but frequently reverts 

 to the parent species it is usually supposed to be derived 

 from that species and is treated as a subdivision of it. 

 But if the new form is as constant as the parent species, 

 the empirical means of demonstrating its relationship 

 are lacking, and the conclusions are drawn from his- 

 torical data and based on analogy; a proceeding which, 

 as we all know, often leads to dift'erences of opinion. 



Besides the historical records the main point in sucli 

 cases is always the proof of the constancy from seed. 

 But inasmuch as the interest of the practical man only 

 extends to the question whether the variety can be con- 

 veniently multiplied by seed and is not concerned with 

 the possibility of occasional reversions, such information, 

 especially in older cases, can only be accepted with cau- 

 tion. 



With this reservation, I propose to give a brief review 

 of some of the better known instances. But before I 

 do this I will call attention to a very beautiful variety 

 which I have not yet found described nor seen in trade- 

 catalogues, but which has appeared in my own cultures. 



