310 Howe : Preliminary notes on the genus Usnea 



ter — at least while field studies of distribution and of environmental 

 effects are so sorely needed — a much better classification seem- 

 ing now, with our present knowledge, improbable. Progress is 

 not always indicated by frequent revision or by a multiplicity of 

 names, a factor which I think to-day we are only too prone to 

 forget. 



It is true that so many different subspecies and forms of Usnea 

 harbata have been described and are recognized that the concept 

 of the typical form has been practically obliterated ; but is this 

 necessary? J?^r^^/^ no doubt now stands for a generic, rather 

 than a specific concept in most students' minds. The diagnosis, 

 as given by Tuckerman, is so brief and indefinite that specimens 

 are rarely referred to it, but are placed under one of the forms, 

 which have enlarged the limits of the species to include many un- 

 typical specimens. 



This state of affairs is not easily remedied. The anterior 



pagination oi Lichen barbatiis o\^y L. floridus in Linnaeus* original 



description * makes it impossible for us to adopt the perhaps 



more logical Lichen floridns for the type form on which to build,t 



unless we abandon Z. barbatiis. That intergradation also exists 



be.tween all forms now classed under Us7iea barbata^ no one can 



doubt, and I am left, therefore, for the present as Tuckerman 



probably was, to accept the classification of his Synopsis of 1882, 



based mainly on Fries, as the only feasible one, and to let my 



field and laboratory studies elucidate wherever and whenever they 

 can, 



r 



The only change that in late years has been made is to raise 

 Jlorida, ceratina, dasypoga, dindpHcata to full species, which, it is true, 

 rids us of the disallowed and absurd quadrinomials, and leaves our 

 taxonomy of the present barbata group as follows ; barbata in 

 this case, perhaps, should have been used to designate a papillate 

 section : 



Usnea florida (L.) Web. 



Usnea ceratina Ach. 

 Usnea dasypoga (Ach.) Fr. 

 Usnea plicata (L.) Web. 



*Sp, PI. 115s, 1156. 1753. 



fit was recognized as such by Fries, Lich. Eur. 19. 1831, *<Typus speciei est 

 formayft-riVa, optime fertilis & fruliculosa." 



