Genetic research in the 1990s and early 2000s showed that the Penstemon genus belongs in Plantaginaceae (Plantain Family), not Scrophulariaceae (Snapdragon Family).

     In North America there are about 243 Penstemon species, which puts it just ahead of Eriogonum (230 species) for endemic North American genera, i.e., these two genera are native only to North America.

    (If we count species numbers for genera that are found in North America and elsewhere, we find that Carex (480 species) and Astragalus (350 species) are more numerous in North America. Astragalus is the largest genus in the world with about 3,200 species, about double the size of the next largest genus, Bulbophyllum.)

    There are more than 36 Penstemons found in the Four Corners area, only surpassed by the Astragalus genus with 61.

   The Penstemon genus has 22 species on this website. Eriogonum has 16 species, Astragalus has 31 species, and Erigeron 28.

    Penstemons are so attractive and popular that there is an American Penstemon Society.   

                                   Who discovered and described the first Penstemon? 

    From his plant collections in Virginia, the well-known botanist (and cartographer, zoologist, and physiologist) Dr. John Mitchell described and named a new species which he placed in a new genus, Penstemon. In 1748 he published the new species and genus. A few years later Linnaeus described this new plant in his famous 1753 "Species Plantarum". However, Linnaeus renamed Mitchell's new plant Chelone pentstemon, placing the plant in an already existing genus, changing Mitchell's spelling of "Penstemon" to "pentstemon", and making "pentstemon" the specific epithet, not the genus.

    The rules of the modern International Code of Botanical Nomenclature indicate that no plant names or descriptions are valid if they were published before 1753, the date of Linnaeus' Species Plantarum. Mitchell published the genus name, "Penstemon" in 1748, so it is not valid. Since Linnaeus placed the plant Mitchell discovered in the genus Chelone, there is no publication of the genus name "Penstemon" in Linnaeus' 1753 "Species Plantarum".

    In his 1762 Icones Plantarum (Illustrations of Plants, page 2), Casimir Schmidel published a description of the Penstemon genus, and this is the earliest publication of the new genus name. Schmidel is now accepted as the author of the Penstemon genus name.

    Schmidel did not, however, describe a particular species in this genus. That description was finally written by the renowned British gardener, William Aiton, "Gardener to his Majesty" from 1759 to 1793. In the King's Gardens Aiton grew plants from the seeds of Penstemon plants collected by Mitchell. In his three volume 1789 "Catalogue of the Plants Cultivated in the Royal Botanic Garden at Kew", Aiton described these plants and named the species, Pentstemon laevigata. This species is the accepted type specimen of the genus. The accepted spelling of the name is now Penstemon laevigatus.

                                        What is the meaning of "Penstemon"?

     Most botanical floras  indicate that the word "Penstemon" is derived from the Greek "pente" ("five") and "stemon" ("thread").  It is stated that Penstemons are so named to point out that they have five stamens (thread-like structures) and/or to draw attention to one of the five stamens, the one that is sterile and distinctly different from the others. This derivation would be supported by Linnaeus' spelling of the genus name: "Pentstemon".  

    However, the genus name was not spelled Pentstemon by Mitchell or Schmidel, and it is not now the accepted spelling. A more accurate etymology of the name " Penstemon" is given by the prestigious Intermountain Flora: "pen" (or "paene") is Latin for "nearly". The genus name then means "nearly a thread", i.e., that there is one structure that is nearly a stamen.

     The botanical term for "nearly a stamen", that is, for a sterile stamen, is "staminode", a modified stamen which does not produce pollen. You can see this staminode, this fifth structure which is nearly a stamen, at the left side of the above photograph.  Notice that the staminode has a few hairs at its tip. Some Penstemon staminodes are very hairy and most project outward toward the end of the lower lip of the floral tube. The hairiness and position of the staminode are important characteristics in determining the Penstemon species, and they are the source for one common name for the genus, "Beard Tongue".

Penstemon barbatus subspecies torreyi (Scarlet Bugler, Scarlet Penstemon, Scarlet Beardtongue) 
Plantaginaceae (Plantain Family)

Semi-desert, foothills. Woodlands, openings. Spring, summer.
Above and left: Mesa Verde National Park, July 21, 2004.

Penstemon barbatus is very common throughout the lower elevations of the Four Corners area, and it is abundant in Mesa Verde National Park. This is a very tall and lanky Penstemon, often growing to four or five feet with an abundance of flowers opening over many weeks. Stem leaves are long, narrow, and widely spaced.

For a very similar species that is also abundant in the Four Corners, see Penstemon rostriflorus.  Although the flowers of the two species are somewhat similar, the forms are quite different: P. barbatus is tall, lanky, and airy whereas P. rostriflorus is much shorter and crowded. Also, P. barbatus blooms in June and July and is flexible and herbaceous throughout.  P. rostriflorus blooms from late June into October and is quite woody at its base.  And most unusual for any of our local Penstemons, P. rostriflorus is commonly evergreen.

Penstemon barbatus was named by Albrecht Roth in 1846 from a collection made in Mexico.

"Barbatus" is Latin for "hairy" or "bearded" and refers to the hairy flower throat of variety barbatus.

Semi-desert, foothills. Woodlands, openings. Spring, summer.
Canyons of the Ancients National Monument, June 6, 2005.

Penstemon barbatus, variety trichander (Greek for "hairy anthers") is found in all the Four Corners counties and in a few counties south of the Four Corners in New Mexico and Arizona.

Semi-desert, foothills. Woodlands, openings. Spring, summer.
Canyons of the Ancients National Monument, May 25, 2016.

A young Penstemon barbatus, just 18 inches tall, shows the difference in the shape of the basal and stem leaves.

Semi-desert, foothills. Openings, shrublands, woodlands.  Spring, summer.
Above: Canyons of the Ancients National Monument, May 10, 2023 and May 11, 2016.
Left: Grandstaff Canyon, Utah, April 14, 2005.

Sprawling or upright growth patterns are common for Penstemon eatonii.  As is true for many Penstemons, flower stalks are often arched over near the tops and straighten as the stem gains strength.  The corolla lobes are very small so that at a glance the flower appears to be a very narrow long closed tube. 

The blazing red of Penstemon eatonii is very common throughout the spring and early summer from trails in Mesa Verde National Park to open expanses of Utah and Arizona.

Daniel Eaton was a nineteenth century American botanist, who collected this plant in 1869 in Utah near Provo.  Asa Gray named the plant in 1872.  (More biographical information about Eaton.)

Semi-desert, foothills. Openings, shrublands, woodlands. Spring, summer.
Grandstaff Canyon, Utah, April 14, 2005 and
Canyons of the Ancients National Monument, May 11, 2016.

Leaf margins are usually crisped (wavy-edged) and leaves are typically lanceolate (but may be oblanceolate or broadly obovate).

Stem leaves are cupped and clasp the stem (no petiole).

The third photograph at left shows basal leaves which are typically a bit larger than stem leaves and have a petiole.

Semi-desert, foothills. Openings, shrublands, woodlands. Spring, summer.
Canyons of the Ancients National Monument, May 17, 2009.

Did you ever wonder, "Where have all the flowers gone"?

Range map © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Range map for Penstemon barbatus

Range map for Penstemon barbatus subspecies trichander

Range map for Penstemon eatonii