[Vor. 1 
188 ANNALS OF THE MISSOURI BOTANICAL GARDEN 
lated. In this arrangement due regard has been given to origi- 
nal descriptions of species and to all details of internal structure. 
Spore collections on glass slides have been made for each species 
whenever possible, and about five thousand mounts of sectional 
preparations in glycerin have been made from collections and 
preserved for reference in connection with internal structure of 
the specimens. From time to time I have taken my Thele- 
phoracee to herbaria where the types of our American species 
are stored and have there painstakingly matched them with 
the types. I have made sectional preparations from a frag- 
ment of each of these types in order to make sure that my 
specimens match the types not only in external characters but 
also in all details of internal structure. The sectional prepara- 
tions of type specimens have been preserved in glycerin. Speci- 
mens from my herbarium which have been so matched with type 
specimens have been used by me later for the determinations 
of subsequent collections. Such methods of investigation are 
probably too laborious and require too much time to become 
popular and they afford little opportunity for the inspirational 
flights attributed to genius, but they do afford a means of deter- 
mining within very narrow limits the species of North American 
T helephoracea. 
I am under especial obligation to Dr. W. G. Farlow for sug- 
gesting this work, for interest in its progress, and for frequent 
access to the Curtis Herbarium for comparisons with types. I 
am indebted also to Dr. C. H. Peck for opportunity to study 
his types in the New York State Herbarium, to the late Dr. 
L. M. Underwood for similar opportunity with the Ellis types 
in the Herbarium of the New York Botanieal Garden, to Dr. 
8. W. Dixon and Professor 8. Brown, of the Philadelphia Acad- 
emy of Natural Sciences, for the privilege of studying in the 
Schweinitz Herbarium, to Sir W. T. Thistleton-Dyer and Mr. 
G. Massee for access to types and authentie specimens in Kew 
Herbarium, to the late Dr. T. M. Fries for the privilege of 
studying in the Herbarium of Elias Fries, at Upsala, and to Mr. 
Lars Romell, of Stockholm, Dr. P. A. Karsten, of Mustiala, 
and Abate G. Bresadola, of Trient, for many authentic speci- 
mens of their own species and for specimens which they had 
compared with types of early authors of Thelephoracem of 
