20 
IOWA ACADEMY OF SCIENCES. 
Thus closes our first period with a record of 12 titles, 
counting the four by Schwartz not separately mentioned 
above, “Species Plantarum” which notices a few lichens 
from North America and Thomas Walter’s “Flora Caro- 
liniana,” 1788, which gives 5 under the name, Lichen. 
Plainly this is the period of beginnings, and it becomes 
apparent that we are still considerably behind Europe in 
licheno-studies at the close of the period when it is stated 
that at the time there were no less than 190 papers and 
books recording lichenological work in Europe, and by no 
means all taxonomic. Of these European titles 54 are 
pre-Linnean (before 1758). But beginnings there must be, 
and the books and papers discussed above are interesting 
and important in that they prepared the way for more ex- 
tended studies. 
THE EURO-AMERICAN PERIOD (1810-1847*) 
Passing to the second period of North American lichen- 
ology, we must mention first the great work of Acharius, 
“Lichenographia Universalis,” in which are described a 
few 7 more than 100 of our lichens, for the most part col- 
lected bv Schwartz, Muhlenberger, Michaux and Menzies 
during the previous period. In this great work by Acharius 
are described only 786 lichens, so that figures prove that 
our known lichen flora of the time amounted to somewhat 
more than one-eighth of the total for the world. “Lichen- 
ographia Universalis” appeared in 1810 and “Methodus 
Lichenum” by the same author in 1814. This second work 
is also valuable for American lichenists, and it may be 
said that the two works by this early European lichenist 
made possible, or at least led to, the appearance of some 
distinctly American works, dealing in part or wholly with 
our lichen flora. Of these the first is Muhlenberg’s “Cat- 
alogue of Plants of North America,” published at Phila- 
delphia in 1818 and containing a list of 184 North Ameri- 
can lichens. This is the first considerable list of our 
lichens published in America, and the number is large for 
the time. In passing it is only fair to note, however, that 
Amos Eaton in his “Manual of Botany of North America,’’ 
