34 
IOWA ACADEMY OF SCIENCES. 
lichens yet given for any State, a complete compilation for 
Massachusetts would surpass it, and I have already com- 
mitted myself to the statement that there are probably 
700 lichen forms within the boundaries of Minnesota. The 
work has added 30 new T North American forms, of which 
ten are new, and has added about 130 lichens new 
to the interior of North America, or to the Mississippi 
valley. The Minnesota papers and some others have con- 
tained extended contributions to geographical and ecolog- 
ical distribution. Also may be mentioned an American 
and European distribution of exsiccati reaching approxi- 
mately 15,000 specimens. 
G. J. Pierce began his work in 1898, and his contribu- 
tions to morphological and physiological problems are im- 
portant as is also the paper by W. C. Sturgis on “The Car- 
pologic Structure and Development of the Collemaceae 
and allied Groups.” Also, during the last three years, 
Mrs. Carolyn W. Harris has been contributing to “The 
Bryologist,” a series of illustrated articles, which must 
prove very helpful to beginners in the study of lichens. 
Finally, it is with regret that I simply record the names of 
E. E. Bogue, H. A. Green, Chas. Mohr, A. C. Waghorneand 
A. B. Langlois, all of whom have contributed to our 
knowledge recently through their collecting or writing. 
Also A. M. Hue’s “Lichenes Exotici,” published in 1S92, 
should have been mentioned with other works by Euro- 
peans, as American students of distribution must refer to 
it constantly, nor has it been possible in the time allotted 
even to mention every helpful paper. 
It is not possible in the present state of knowledge to 
give the exact number of species of our lichens described 
since Tuckerman’s time, or to give exactly the whole num- 
ber of lichens added to our flora siuce 1888. However, 
the wdiole number of lichen forms added is not far from 
360, and the number of new ones 265. This gives us a 
lichen flora of approximately 1,600 species and varieties. 
However, the post-Tuckermanian work is by no means to 
be regarded as merely additions to the flora, for the work 
of Schneider and the morphological, physiological and 
