28 
IOWA ACADEMY OF SCIENCES. 
in the two volumes cf the “Synopsis”, for North America, 
is approximately 1050, and this number is no doubt con- 
siderably below the whole number of North American lich- 
ens known by Tuckerman. Thus within the period, the 
number has grown from 295 to at least 1050, and following 
Willey’s “Supplement”, of 1887, no doubt 1225 or 1250 
comes nearer to the number. 
Tuckerman was pre-eminently a systematist, but some 
words are in order regarding his views on some other 
questions of lichenology. In regard to the theory of 
Schwendener as to the dual nature of lichens, he was more 
guarded in bis statements than many of the other syste- 
matic lichenists of his day. While he readily admitted 
that there were some arguments in favor of the theory, 
he seems finally to have adopted the views of Minks, and 
like Muller and some others of his day thought that he 
had himself demonstrated the existence of the “microgon- 
idia.” This he regarded as establishing a boundary line 
between lichens and fungi. It is pleasant to note, how- 
ever, that during the years of sharp debate, Tuckerman 
was always careful and considerate in his treatment of the 
question. It is also quite as pleasant a task to record that 
in a short paper entitled “Can Lichens be Identified by 
Chemical Tests,” Tuckerman remarks that his own obser- 
vations have led him to believe that such tests are scarcely 
reliable, a view which I suppose meets the approval of 
later lichenists generally, since we have reached more 
definite knowledge regarding the anatomy of these plants. 
Excellent memoirs of Tuckerman by Willey, Gray and 
Farlow give much more of detail than can be incorporated 
here . Finally a considerable amount of good collecting 
and making of lists of lichens from limited areas must be 
passed unnoticed, the w T hole number of titles for the 
period amounting to 175. 
THE RECENT PERIOD (1888 TO THE PRESENT TIME). 
There seems to be a feeling extant that American lichen- 
ology has been neglected since the death of Tuckerman; 
but the facts to be brought out below do not bear out this 
