Reference:Keck1937a
Verbatim text: Keck, D. D. 1937. Studies in Penstemon IV. The section Ericopsis. Bull. Torrey Bot. Club 64: 357–381.
Author: Keck, D.D.
Year: 1937
Title: Studies in Penstemon IV. The section Ericopsis
Journal: Bull. Torrey Bot. Club
Volume: 64
Pages: 357–381