Penstemon Schmidel. Beardtongue, Penstemon.
Contributed by Alan S. Weakley and Dwayne Estes
A genus of about 280 species, perennial herbs and shrubs, of w. North America, e. North America, and (a single species) ne. Asia.
Ref: Bennett (1963); Clements, Baskin, & Baskin (1998); Estes (2012); Freeman (2019d) In Flora of North America Editorial Committee (2019); Pennell (1935). Show full citations.