The lichen genus Physcia in North America
By: by John W. Thomson.  With 49 photographs on 25 plates and 37 distribution maps.
Series: Nova Hedwigia. Beihefte -- no. 7.; Beihefte zur Nova Hedwigia -- Heft 7.
Publisher: J. Cramer
Published: 1963
Place of publication: Weinheim
Language: eng
Number of pages: 172
Subjects: Physica.; Lichens -- North America.