Northern Prairie Wildlife Research Center
One of our most beautiful grassland plants, large beardtongue has a disjunct distribution in North Dakota. One inhabited area is the group of counties near the Missouri River south of and including Oliver; the other is the Red River Valley. We are at the northern edge of the natural range of the species, for it grows from North Dakota and Wisconsin southward to New Mexico. The plant is commonly cultivated and has escaped in parts of New England.
Large beardtongue is a perennial up to three feet tall from a dense mass of tan roots. The smooth waxy leaves are opposite each other, and clasp the stem. The largest pair of leaves is at the bottom of the plant. These leaves are two to three inches long. The flowers also grow in pairs; these pinkish-lavender blossoms are nearly two inches long. Fruits are capsules nearly an inch long filled with angular, dark seeds.
Look for large beardtongue in very sandy soil such as found along rivers and old glacial river deltas. Livestock grazing seems to have little effect on the abundance of this species. The Kiowa in New Mexico made a decoction of the roots of this plant to alleviate toothache.
Beardtongues belong to the figwort family (Scrophulariaceae), which derives its name from the supposed cure of scrophula and figwarts attributed to members of this family by the early herbalist-physicians. Beardtongues are so called because they have a single sterile stamen that bears a tuft of hairs. This thread-like male organ protrudes from the flower like a "tongue". There are four fertile stamens in addition, hence the generic name Penstemon, from the Greek paene, "almost", and stamon, "thread" (filament) or "almost a stamen." The specific name grandiflorus means "large-flowered" in botanical Latin. Large beardtongue was first described for science by the eminent English botanist-naturalist Thomas Nuttall (1786-1859).