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2 
' 
re 
* 
May 10, 1913. Vor, I, pp. 15-25. 
_PROCEEDINGS 
tee 
OF THE 
THOREAU MUSEUM OF NATURAL HISTORY. 
MIDDLESEX SCHOOL, 
CONCORD, MASSACHUSETTS. ; 
f 
THE USNEAS OF THE WORLD, 1752-1912. 
WITH CITATIONS, TyPE LOCALITIES, ORIGINAL DESCRIP- 
TIONS AND KEYS. 
PART I. NORTH AMERICA. 
BY R. HEBER HOWE, JR., ASSISTED BY J. P. WARBURG AND C. P. WINSOR. 
The purpose of this paper is to provide lichenologists 
with the citations, original descriptions, and type localities of 
alf described species of the genus Usnea. These have been 
brought together from many sources, some of which, e. g. 
Stirton, are exceedingly difficult-of access. By their compila- 
tion it is hoped to aid the advancement of our knowledge of 
this cosmopolitan genus. 
Part I deals with only the Usneas of North America. 
These are numbered and all those which have a type locality 
more specifically stated than North America, have been 
located upon the accompanying map. There then follow cita- 
tions, type localities, and original descriptions. A key for 
the species of this continent is appended, based largely, by 
necessity, upon the salient points gathered from the descrip- 
tions, as material of all the described species is impossible of 
access. Whenever the disposition of the type specimen is 
known, the location of the herbarium is given. 
15 
