Penstemon, the beardtongues, is a large genus of North American and East Asian flowering plants formerly placed in the Scrophulariaceae family. Due to new genetic research, it has now been placed in the vastly expanded family Plantaginaceae.
They have opposite leaves, partly tube-shaped, and two-lipped flowers and seed capsules. The most distinctive feature of the genus is the prominent staminode, an infertile stamen. The staminode takes a variety of forms in the different species; while typically a long straight filament extending to the mouth of the corolla, some are longer and extremely hairy, giving the general appearance of an open mouth with a fuzzy tongue protruding and inspiring the common name beardtongue.Most penstemons are deciduous or semi-evergreen perennials, the remainder being shrubs or subshrubs. Heights can range from 10 cm to as much as 3 metres.
The one Asiatic species previously treated in Penstemon is now placed in a separate genus Pennellianthus. This leaves Penstemon a mostly nearctic genus, with a few neotropical species. Although widespread across North America, and found in habitats ranging from open desert to moist forests, and up to the alpine zone, they are not typically common within their range.