A pamphlet prepared by E. C. Ogden for use in plant taxonomy, June, 1943. The 5-page list includes the species of ferns, clubmosses, horsetails, and quillworts which had been collected in Penobscot County, Maine.
Ogden, E. C., "Check-list of Ferns of Penobscot County, Maine" (1943). Maine History Documents. 514.
publisher's version of the published document