Howe: Preliminary notes on the genus Usnea 311 



This raising was done by Herre in a most wholesale fashion ; 

 Jiirta and rtibiginea being included, and though a follower of Zahl- 

 bruckner, he raises pUcaia to specific rank, which the latter in 

 Engler & PrantI does not do. All this too, without a reason, 

 except the admission that *'the species [are] not always well de- 

 fined and apparently intergrading." Such revisions only serve to 

 burden, as a rule, the synonymy, and for the present, at least, I am 

 unwilling to abandon Tuckerman, though I beheve with further 

 study a more lucid and correct classification can be adopted ; and 

 I believe that Herre's, based I suppose on that of Hoffmann, 

 though now seeming somewhat warranted, will prove inadequate, 

 and is not allowable according to the methods now followed in 

 nomenclature. 



I have used the life zones in outlining the range of the various 

 species, though no doubt plants adhere less closely to such areas 

 than do the animals, being dependent so largely on substrata and 

 conditions of moisture. But to a surpi'ising degree, a nice rela- 

 tionship is shown by this genus. 



The following purely artificial key to the genus as represented 

 in New England may be of some aid in determining the species oi 

 this difficult group : 



Thalhts papillate 



■ 



I, Terete. 



A. Erect; apothecia abundant, terminal. 



Rigid ; apotbecia middling-sized ....^ U. barhata florida. 



Subcrustose, strigose, short-branched ; apothecia large... [j/;7^t?ja].* 



B. Erect, rarely subpendulous ; apothecia wanting (or very 



rare). 



Rigid, generally hirsute, sorediate yivia^. 



Rusty red \j'uhiginea'\, 



C. Subpendulous (maximum length, 30 cm.) ; apothecia 



rare or wanting, sessileon main filaments or subterminal. 

 Rigid, coarse; fibrils rectangularly arranged U, barbata, 



D. Pendulous (average length, 60 cm.) ; apothecia (rare or 



very uncommon as represented in this region). 

 i Rigid, coarse; fibrils, if present, rectangularly arranged.. 6^ barhata ceratina. 



Pliant, slender (except at very base) ; fibrils rectangularly 



arranged U> barbata dasypoga. 



Pliant, slender; lateral fibrils wanting U, barbata plicata, 



Thallus epapillate 



E. Lax, slender (average length 30 cm. ); fibrils capillaceous ; 



apothecia not common • U, trichodea. 



* [] indicates contingent forms for which a name is a burden. 



