26 THE AMERICAN BOTANIST 



away, not by a great convulsion of nature, but by the silent 

 though deadly onslaughts of some microscopic pest ? 



The; Species Conception. — Is there any such thing as 

 a species? Time was when even the botanizer believed him- 

 self capable of distinguishing species in all but the most diffi- 

 cult genera, l)ut the technical botanist has continued to refine 

 his idea of species until even the specialist finds it almost im- 

 possible to correctly interpret species made by others working 

 in his chosen field. An excellent illustration of this is found 

 in a recent contribution from the United States National Her- 

 barium in reference to the allies of SclagincUa riipcstris, one 

 of the fernworts. The author, G. P. \'an Eseltine reports 

 that L. M. Underwood's type sheet of SclagincUa arenicola 

 contains twelve specimens, six of which are true S. arenicola 

 and the other six represent probably two other distinct species. 

 In his day, Underwood was reputed to be an accomplished 

 and skillful species-splitter, but he certainly must have been a 

 bungler in comparison with present day operators, if he could 

 mistake two different species for a third one and mount all 

 on a single sheet as typical of a new species. It is likely, how- 

 ever, that no new species of SclagincUa have been discovered 

 in eastern North America since Underwood worked with the 

 group. The so-called new species are simply the old species 

 split still finer. Carried to its logical conclusion, the modern 

 species conception makes the individual and the species synony- 

 mous and thus ends the matter. It has l)een well said, that 

 species are merely judgments. All that modern refinements 

 in species making has shown, is that the ordinary species has 

 no definite boundaries, but may be considered anything the 

 namer cares to make it. The ecologist who has investigated 

 the causes thai affect the external appearance of plants, is 

 often anuised at tlie inii)ortance attached to some insignificant 

 variation in jflanls by the .systematist who seizes upon it to 



