Reference:Johnson1969a
Verbatim text: Johnson, R. R. 1969. Monograph of the plant genus Porophyllum (Compositae: Helenieae). Univ. Kansas Sci. Bull. 48: 225–267.
Author: Johnson, R.R.
Year: 1969
Title: Monograph of the plant genus Porophyllum (Compositae: Helenieae)
Journal: Univ. Kansas Sci. Bull
Volume: 48
Pages: 225–267