IOWA ACADEMY OF SCIENCES. 
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lished in 1860, mentions a considerable number of our 
lichens with descriptions. In a few minor papers also, 
Fries touches North American lichens, but Nylander, who 
at the time of his death was undoubtedly first in his 
knowledge of lichen species, influenced American lichen- 
ology of the period more than any American except Tuck- 
erman, and possibly Henry Willey. Nylander’s titles deal- 
ing wholly or in part with our lichen flora number no less 
than two dozen. Of these, eight are manuals or mono- 
graphs, dealing with the general distribution and taxon- 
omy of lichens as a whole or with certain genera, and 
belong to the present period. Of the remaining 16 titles, 
all but three belong to the present period, and the 16 con- 
tain descriptions of nearly 200 new North American 
lichens. This is a rather remarkable contribution for a 
foreigner, but Nylander was doubtless too much given to 
species-making; and it is not a little unfortunate that he 
depended too much upon chemical tests in his determina- 
tions, while his diagnoses belong to the older, rather brief 
and inadequate type. So far as we are able to ascertain, 
this great lichenist began his work on American lichens 
with the publication of “ Lichenes collecti in Mexico”, a 
Fr. Muller, in 1858, and his interest in our flora never 
waned till the closing year of his life, his death occurring 
in 1899. In 1895, on sending Nylander a copy of “ The 
Lichens of Iowa”, he says in his reply, “ Yous etes dans 
l’erreur ent disant ” “ it is generally admitted that a lichen 
is a dual organism ” “ Cela n'est qu’une calomnie et n’est 
nullement serieux ”. Having begun my work on lichens 
about the close of the period with which we are now deal- 
ing I was surely serious in the statement, and calumny 
was farthest from my thought. However, doubtless the 
words quoted express not only Nylander’s view, but also 
that of nearly all of the older systematic lichenists of 
America and Europe, with some of whom I was beginning 
to correspond at the time. 
Krempelhuber/in his “Geschichte,” gives the original 
names of nearly all American lichens described previous 
to 1870 and also furnishes a very valuable review of our 
