476 



collected, the plants raised from which have likewise passed com- 

 pletely one into the other ; also that under cultivation the same va- 

 riable characters are exhibited. 



These are important points ; but now the question presents itself, 

 Whence arises this infinite variety ? 



It may be that there is one species only, which, when far removed 

 from others and every possibility of hybridization, has a natural ten- 

 dency " to sport " in the seedlings, giving rise to an endless variety. 



On the other hand it may be that there are three or four species, 

 or more, forming a group, which are readily affected by hybridization, 

 the seedlings from any one of which may, under such influence, show 

 every imaginable intermediate state.* 



Or it may be that there are many species, the individuals of which 

 have a tendency, without hybridization, to vary and "sport" from 

 seed ; the seedling from one species so closely approximating the 

 seedling from another species, as scarcely to be distinguishable. It 

 is only necessary to refer those who have examined extreme forms of 

 Polystichum lobatum, var. (?) lonchitidioides, to its close resemblance 

 to P. Lonchitis ; and yet it is known that the former under cultiva- 

 tion assumes the common form of P. lobatum, while on the other 

 hand P. Lonchitis retains its character, or quickly regains it, where 

 the original plant has taken the form of P. lobatum " lonchitidioides," 

 by having grown in a shaded place. 



Till these intricate questions are settled, who can be justified in 

 saying that such are species or such are only varieties, or much more 

 in saying that there is a "moral," or even "scientific, obligation" for a 

 person holding one view to declare his error ? 



Because seeds procured from wild plants in Ireland or the Pyrenees 

 produce infinite variety, we have no proof against the existence of 

 several species : and because intermediate forms are found abun- 

 dantly in the Pyrenees as well as in Ireland, it may be answered by 

 way of argument, that like causes under like circumstances produce 

 like effects. 



Until extreme forms have been cultivated, singly and far apart 

 from others of the group, for a season or two, and seedlings have been 

 raised from these, which not only vary, but actually produce the op- 

 posite extreme, it appears to me that no one can say with certainty 

 that there are not several species which have a tendency " to sport," 



* As in the case of Pvrus Aria and P. Aucuparia, where by hybridization every 

 intermediate form has been produced. 



