Penstemon haydenii was originally described in 1891 by Sereno Watson and was named for its first collector, the geologist and explorer Ferdinand V. Hayden, who probably collected it in the late summer of 1857 in the" Sand Hills of Loup Fork," Nebraska. The Hayden specimen which Watson saw in the Gray Herbarium at Harvard University had evidently been labeled with an incorrect location. Watson did not base his description on that early specimen but upon a more complete specimen, also in the Gray Herbarium, taken by Herbert J. Webber in Thomas County in 1891; so the Webber specimen, not the earlier Hayden collection, was designated by Francis W Pennell as the type specimen. Between the original Hayden collection and 1968, only about eight collectors had taken the plant, and knowledge of it was very limited. I collected it with Robert Kaul and Dennis Brown in 1968, but I was not aware of its extremely limited distribution until about 1974, when work began on checklists for the Great Plains Flora project.
Sutherland, David M., "Historical Notes on Collections and Taxonomy of Penstemon Haydenii S. Wats. (Blowout Penstemon), Nebraska's Only Endemic Plant Species" (1988). Biology Faculty Publications. 34.