Anonymous, Calif. Fungi
Herbarium of the University of California. [1- ? 1425]

Cornell University, Plant Pathology Herbarium
Catalog #: CaliforniaF.00831
s.n.
Sphaerotheca humuli (DC.) Burrill

University of Michigan Herbarium
Catalog #: 309401
J. P. Tracy #17905 24 August 1947
Sphaerotheca humuli var. fuliginea (Schltdl.) E.S. Salmon
USA, California, Humboldt, Trinity Summit, Box Camp.

Field Museum of Natural History
Catalog #: C0286336F
J.P. Tracy #17905 24 August 1947
Sphaerotheca humuli (DC.) Burrill
USA, California, Humboldt, Trinity Summit, Box Camp

University of Wisconsin-Madison Herbarium
Catalog #: WIS-F-0056391
Joseph P. Tracy #17905 24 August 1947
Sphaerotheca humuli var. fuliginea (Schltdl.) E.S. Salmon
United States, California, Humboldt, Trinity Summit, Box Camp