List of lichens collected in the Yukon region by Mr, R. S. Williams 
R. HEBER Howe, Jr. 
During the winter of 1910 Mr. R. S. Williams sent me a 
duplicate set of lichens which he had collected in the Yukon 
region in 1898 and 1899. Mr. T. A. Williams had examined the 
collection several years before and determined a large number of 
them, but his work had been only casual and he professed no criti- 
cal study of the material. Both Mr.T.A. Williams and Miss C. E. 
Cummings were given duplicate sets, though Miss Cummings’ was 
incomplete. I forwarded the crustose species at once to Dr. H. E. 
Hasse of Sawtelle, Cal., and the specimens of Cladonia, Stereocaulon 
and Baeomyces to Dr. L. W. Riddle of Wellesley College, who also 
lent his aid on several species of other genera, while I have studied 
the remaining foliaceous and filamentous species. One unusual 
Cladonia bearing a new manuscript name given by Mr. T. A. 
Williams I sent to Dr. L. Scriba of nega To all these 
gentlemen grateful thanks are due. 
Family SPHAEROPHORACEAE 
. Sphaerophorus coralloides Pers. No. 32, Sheep Camp, Dyea 
Cr., Mar. 1898, fertile; no. 70, above Lake Lindeman, May 
20, 1898, sterile. 
. Sphaerophorus fragilis (Crantz) Pers. No. 90, Lake Lindeman, 
Lal 
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May 5, 1898, sterile. 
Family ARTHONIACEAE 
3- Arthonia (Allarthonia) patellulata var. alnicola Nyl. No. 62, 
Dawson, Mar. 1899, fertile. 
Family LECIDACEAE 
4. Buellia papillata (Sommf.) Tuck. No. 86, Lake Lindeman, 
May 15, 1898, fertile. 
5. (?) Buellia scabrosa (Ach.) Koerb. No. 79, Lake Lindeman, 
May 28, 1898, fertile. ‘‘ Probably correct—scanty, about all 
used up in making examinations.’’—Hasse. 
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