NORTH AMERICAN USNEACEAE. 139 
‘papers on the genera Usnea,t Evernia,® Alectoria® and 
Oropogon,’ will be found a complete history of the type 
specimens, augmented by a few special papers (Bull. Torr. 
Bot. Club 37: 605-609. 1910 and 1. c.), including a report 
on the Linnean Herbarium (Bull. Torr. Bot. Club 38: 199- 
203. 1912). It has been only through the great kindness 
and generosity of the curators of the herbaria of both this 
country and Europe that this knowledge, which I consider 
vital, has been gained. Below is given the list of authors, 
museums and their curators, to whom I am_ gratefully 
indebted. 
AcHARIUS: Universitetets Botaniska Institution, Helsingfors, Fin- 
land—Dr. Fred. Elfving. Linnean Society of London, Burlington House, 
London, England—Dr. B. Daydon Jackson. 
Anzi: British Museum of Natural History, London, England— 
Dr. A. B. Rendle. Museum d’histoire naturelle, Paris, France—Dr. L. A. 
Mangin. 
BELLARDI: Istituto ed Orto Botanico della R. Universita, Turin, 
Italy—Dr. O. Mattirolo. 
Cosson: Museum @histoire naturelle, Paris, France—Dr. E. 
Perrier. 
CroMBIE: British Museum (Natural History), London, England— 
Dr. A. B. Rendle. 
DE Noraris: Istituto e orto Botanico, Rome, Italy—Dr. R. Pirotta. 
DitLeNIus: Botanic Gardens, Oxford, England—Dr. S. H. Vines. 
Dusy: Universitets Botaniska Institution, Upsala, Sweden—Dr. 
H. O. Juel. 
EnRHART: Royal Botanic Gardens, Kew, London, England—Col. 
D. Prain. Linnean Society of London, Burlington House, London, 
England—Dr. B. D. Jackson. 
4 A Manual of the Genus Usnea, as represented in North and Middle 
America, north of the 15th parallel. Bull. Torr. Bot. Club 37 : 1-18. 
1910. 
5 The Genus Evernia as represented in North and Middle America. 
Bot. Gazette 51 : 431-442. 1911. 
6 American Species of Alectoria occurring north of the 15th parallel. 
Mycologia 3: 106-150. 1911. 
7 Mycologia 4:152-156. 1912. 
