- 7 8- 



views of that author, whatever criticism is offered here will apply- 

 equally to both publications. 



The treatment of species and varieties is especially open to 

 severe criticism, there being too much of a disposition to recog- 

 nize the deplorable tendency among certain writers to individual- 

 ize plants and multiply species needlessly. For example, in the 

 ferns alone, of the 196 so-called species enumerated, at least 

 twenty (20), if not more, are not valid species in the same sense 

 as Polypodium vulgare, or as recognized by a majority of the 

 best authorities. 



It should be stated here for Mr Maxon's benefit that Mr. Gil- 

 bert has accepted several of these questionable species, so that, 

 perhaps, it may appear to be, at least in some cases, a mere mat- 

 ter of opinion ; but this much is certain, the characters on which 

 such specific recognition rests are not such as are generally ac- 

 cepted by the best workers as fundamentally and structurally dis- 

 tinct, but are such as are dependent on size, texture, compounding 

 of the lamina, and other characters that can be shown to be ex- 

 tremely variable and wholly unreliable. 



No better example could be adduced to illustrate specific dif- 

 ferences than the case of Botryckium ternatum and B. Virgin- 

 ianum. These two species are structurally and fundamentally- 

 distinct in every way, and there are no intergradient forms between 

 them, so that it is impossible ever to mistake one for the other. 

 B. matricaricefolium and B. lanceolatmn may not always be as 

 distinct structurally, but fundamentally their vernation and spores 

 are as distinct as those of ternatum and Virginianwn ; but in the 

 group of forms that make up the aggregate of B. ternatum the 

 vernation and spores are identical, as I have previously shown, 

 and there are no fundamental characters whatever to justify the 

 extreme segregation into which Prantl and Dr. Underwood have 

 attempted to separate the group. 



In the '* Ophioglossaceae " the views of Dr. Underwood are 

 adopted without any reservations, and some twelve (12) or thirteen 

 (13), at the most, valid species are raised to twenty-three (23) on 

 characters scarcely of varietal importance! Ophioglossum 

 arenarium E. G. Britton is a mere form of 0. vulgatum, and is 

 now so regarded by Mr. Clute and Mr. Gilbert; and so of O. 

 Alaskanum (E. G. Britton), and Engehnanni Prantl, which was 

 previously named var. mucronatum by Butler. 0. Calif ornicum 



