As the subgenuses have some taxonomic uncertainty, the species are arranged alphabetically by name in the lists.
As of 2024[update] there are 281 species and seven natural hybrids, according to Plants of the World Online (POWO).
[2] These 281 species of Penstemon are considered valid by both World Flora Online (WFO) and Plants of the World Online (POWO), with the exception of Penstemon grandiflorus.
[1][2] In both POWO and WFO, it is regarded as a synonym of Penstemon bradburyi.
However, P. grandiflorus continues to be widely used as the correct species name in North America, including by the Flora of North America and the USDA Natural Resources Conservation Service PLANTS database (PLANTS).