Source:
Kofoid, Charles Atwood ; Biological Stations of Europe ; Washington, DC : Government Printing Office, 1910 ; Bulletin (United States. Bureau of Education), 1910, no.4 ; Plate XLVI-B ; Most materials
Source:
Kofoid, Charles Atwood ; Biological Stations of Europe ; Washington, DC : Government Printing Office, 1910 ; Bulletin (United States. Bureau of Education), 1910, no.4 ; Plate XLVI-A ; Most materials