Verbatim text: Straw, R. M. 1966. A redefinition of Penstemon (Scrophulariaceae). Brittonia 18: 80–95.
Author: Straw, R.M.
Year: 1966
Title: A redefinition of Penstemon (Scrophulariaceae)
Journal: Brittonia
Volume: 18
Pages: 80–95