Cite

U.S.P.R.R. Ex. & Surveys 32d parallel California. Botany, Plate VI. Aplopapappus sph'rocephalus.

MLA

Ackerman Lith., New York, and New York. U.S.P.R.R. Ex. & Surveys 32d Parallel California. Botany, Plate VI. Aplopapappus Sph'Rocephalus. 0AD. https://collections.library.yale.edu/catalog/2015798.

APA, 6th edition

Ackerman Lith., N. Y., & York, N. (0 C.E.). U.S.P.R.R. Ex. & Surveys 32d parallel California. Botany, Plate VI. Aplopapappus sph'rocephalus. [Lithographs, Planographic prints]. https://collections.library.yale.edu/catalog/2015798.