Verbatim text: Clements, R. K., J. M. Baskin, and C. C. Baskin. 1998. The comparative biology of the two closely-related species Penstemon tenuiflorus Pennell and P. hirsutus (L.) Willd. (Scrophulariaceae, section Graciles): I. Taxonomy and geographical distribution. Castanea 63: 138–153.
Author: Clements, R.K., Baskin, J.M., Baskin, C.C.
Year: 1998
Title: The comparative biology of the two closely-related species Penstemon tenuiflorus Pennell and P. hirsutus (L.) Willd. (Scrophulariaceae, section Graciles): I. Taxonomy and geographical distribution
Journal: Castanea
Volume: 63
Pages: 138–153