Verbatim text: Crosswhite, F. S. 1965e. Revision of Penstemon (Sect. Penstemon) Series Graciles (Scrophulariaceae) with a Synopsis of the Genus. M.S. thesis. University of Wisconsin.
Author: Crosswhite, F.S.
Year: 1965e
Title: Revision of Penstemon (Sect. Penstemon) Series Graciles (Scrophulariaceae) with a Synopsis of the Genus