Fink: Henry Willey 
51 
Tuckerman. The names are given in our list of writings at the 
close of this paper. 
Excepting the Tuckerman herbarium, now at Harvard Uni- 
versity, Mr. Willey’s herbarium, now in the Smithsonian Institu- 
tion at Washington, was the largest and most valuable private 
collection of lichens of his day, if indeed second to any other 
American lichen herbarium of any time, brought together by one 
person. The writer has had occasion to consult the Willey col- 
lection at Washington and knows personally of its great value. It 
contains about 10,000 specimens, many of them very rare and 
valuable. 
Mr. Willey belonged to a type of students of lichens now 
extinct, or nearly so. He was never able to accept even the 
“ dual hypothesis,” but believed that the green or the blue-green 
cells were part of the lichen, just as chloroplasts are parts of 
higher plants. But some botanists of our day would be quite as 
much shocked to be told that both this view and the “ dual 
hypothesis ” are gone for those who have studied lichens in the 
light of modern morphology, physiology, mycology and cytology, 
and that all botanists will some day agree that the lichen is a 
fungus pure and simple, parasitic on an alga. Again, Mr. 
Willey, with others of his day, felt certain of the integrity of the 
group Lichenes. But this group is certain to be distributed gen- 
erally among other Ascomycetes in the future. The accumulat- 
ing evidence from the study of life histories of Ascomycetes 
leaves no alternative. It is not to the discredit of Mr. Willey 
that he held views very prevalent in his day. He did excellent 
work on lichens, but every person who studies these plants in our 
day should seriously consider their nature and proper classi- 
fication. 
Below is given the list of Mr. Willey’s papers on lichens. 
Willey, H. A fern new to our flora. Am. Nat. 1 : 432, 433. 187. The 
paper also contains notes on 3 common lichens. 
Willey, H. American lichenography. Proc. Essex Inst. 5: 191-196. 1867. 
Gives a fairly good list of publications on American lichens up to 1867. 
Willey, H. Lichens under the microscope. Am. Nat. 4 : 665-675. f. 739- 
153. 1871. A popular discussion of microscopic structure. 
Willey, H. The spores of lichens. Am. Nat. 4: 720—724. 1871. A valu- 
able discussion of the diagnostic value of number and size of spores. 
