IOWA ACADEMY OF SCIENCES. 
33 
Tuckerman. The departure from Tuckerman’s classifi* 
cation and especially the change in generic limitations 
seem in the main to be an improvement, while the chap- 
ters on morphology and physiology can not fail to be help- 
ful to all students of lichenology. All in all the book is 
one of the most helpful contributions to lichenology. 
However, to some just criticism which the work has 
received, I may be permitted to add that careful studies of 
the thalli and apothecia of some 500 species of the genera 
given in the text has shown plainly that a considerable 
number of the statements and drawings intended to bring 
out generic characters are surely based upon the exami- 
nation of a small number of species. Finally, Schneider’s 
briefer “Guide to the Study of Lichens,” which appeared 
in 1898, will surely prove valuable to the beginner in the 
study of lichens. 
H. E. Hasse, of California, has in recent years con- 
tributed largely to a knowledge of the lichen flora of his 
State. His first paper appeared in 1895, and quite a number 
has been added since. In these papers Hasse has listed 434 
lichens from California and the coast islands. Of these 96 
were new to North America and 64 new species. Dr. Hasse 
has had the aid of Stizenberger, Nylander and Zahlbruck- 
ner, and the work still in progress has already added more 
lichens to our flora than any other of the present period. 
The first paper by the present writer appeared in 1895, 
and others have followed at frequent intervals, aggregating 
24 titles and about 500 pages. For the work in Iowa, 226 
species have been published from various parts of the 
State. The vicinity of Fayette, Iowa, the only area in the 
State even fairly well studied, has yielded 205 forms which 
have been published, while a number of other species 
from the region and recently determined as old or new 
species, have not yet been published. Thus it is apparent 
that our knowledge of the lichen flora of Iowa is yet quite 
incomplete. The work in Minnesota is much more com- 
plete, the whole number of forms listed being approxi- 
mately 500. However, while this is the largest number of 
