222 Best : North American Pseudoleskea 



something, should possess an element of constancy and should 

 not be founded on such variations as originate in the changing 

 conditions by which all plants are more or less influenced. The 

 fashionable tendency to multiply species on the pretext that this 

 is the panacea for all systematic troubles, is not always the out- 

 come of a fuller knowledge on the part of those who make them 

 but often is due either to ignorance of what others have done 

 along the same lines or a desire to appear to know more than 

 their confreres. In the making of species, as with many other 

 things, the better course lies between the extremes and, no matter 

 how often we divide and subdivide our plants, it is quite possible to 

 continue the process along the same lines and for the same reasons 

 until each individual has a specific name of its own. 



The members of the genus Pseudoleskea are mountain-loving 

 plants which flourish best at high altitudes. When they appear 

 at lower levels they not infrequently show their inability to adapt 

 themselves to their environment by taking on atavistic or de- 

 pauperate forms. But sparingly collected and then usually with- 

 out fruit their consideration from a systematic standpoint is some- 

 what difficult. By an attentive study, however, of considerable 

 material, American and European, it has been possible to acquire 

 a fair conception of the central types that underlie them and to ar- 

 range them in accordance with more modern views of nomen- 

 clature. 



Undesirable as it is in some respects, it becomes necessary to 

 reduce Lescuraea to the rank of a subgenus. American plants ef- 

 face the lines of separation between it and Pseudoleskea. The 

 gametophyte characters of P. radicosa and P. rigescens connect 

 so closely with those of the European Lescuraeas as to leave no 

 doubt of their being congeneric. On the other hand the sporo- 

 phyte characters of P. radicosa closely connect with those of P. 

 atrovirens while those of P. rigescens do the same with the sporo- 

 phyte characters of Lescuraea striata. Indeed, so closely related 

 are these last that Schimper* refers to P. rigescens under Les- 

 curaea as a "species Aniericanae distinclissima" Sullivant,f how- 

 ever, held that P. rigescens (Leskea rigescens Wils.) was simply a 



*Syn. Muse. Eur. 2 : 621. 1876. 



f Ms. Notes on Pseudoleskea in Gray herb. 



