Whitewand beardtongue, Tubed beardtongue

Penstemon tubaeflorus is also sometimes spelled Penstemon tubiflorus.

The word “penstemon” is derived from the Greek words, ‘pente’ meaning five and ‘stemon’ meaning thread, which is taken to mean stamen. The word “tubaeflorus” means trumpet-flowered and the word “tubiflorus” means tube flowered.

Common names of this lovely flower include Tubed beardtongue, Whitewand beardtongue and Trumpet penstemon.

The sparkling white flowers of Tubed beardtongue are arranged in loose panicles (clusters) at the termination of the stem. Flower clusters occur on individual branches in a cylindrical pattern. Individual flowers are up to an inch in length and pubescent with a narrow tube and large flat face.

Four stamens occur with curved filaments tipped by blackish anthers. A glabrous style protrudes beyond the stamens. The green calyx often has a glandular pubescence.

Penstemon tubaeflorus is a perennial growing to 3 feet tall. A single mature plant may have several stems arising from a basal rosette. These stems do not branch. They are smooth, stout and glabrous (without hairs). A reddish/purple tint may be seen toward the base. The stem typically becomes a brilliant scarlet after flowering, when the seed pods become ripe. Woody stems from the previous season often persist and are seen alongside the new growth.

Mature plants have both basal and cauline (stem) leaves. The large basal leaves are numerous. Stem leaves are opposite and sessile or clasping. These leaves are mostly located on the lower half of the stem, gradually becoming more widely spaced and smaller. Each set of stem leaves is rotated from the previous pair.

After blooming, the flowers are replaced by green seed pods that transition from green to a reddish purple that rivals the beauty of the flowers. Once the seed pods ripen to dark brown, they release their numerous tiny seeds.

Penstemon tubaeflorus has a more narrow neck than other penstemons, hence it is often visited by small bees such as Miner bees.

I've documented visits by the Miner bee commonly known as the Abrupt Digger Bee (Anthophora abrupta) as well as American Bumble bees (Bombus pensylvanicus.

Mason bees (Osmia distincta) and a wasp (Pseudomasaris occidentalis) are known to visit the flowers (Clinebell, R. R., & Bernhardt, P. 1998. The pollination ecology of five species of Penstemon (Scrophulariaceae) in the tallgrass prairie. Annals of the Missouri Botanical Garden, 126-136).

Spicebush swallowtail butterflies and the Ruby throated hummingbird occasionally visit the flowers for nectar.

Penstemon tubaeflorus is primarily a prairie plant. It may also be found found limestone glades and at woodland edge. It prefers, perhaps requires, well-drained soil.

Penstemon tubaeflorus is primarily found in Arkansas, Missouri, Oklahoma and Kansas. However, smaller populations occur in western Tennessee, Texas, Oklahoma and Kansas. It is listed as Critically Imperiled in Tennessee, Indiana and Iowa, Vulnerable in Illinois and Secure in Kansas. All other states show No Status Rank on Natureserve.

In Arkansas, Penstemon tubaeflorus has a C-value of 8, meaning it has a strong fidelity to intact habitats. Overall, this has become an uncommon plant. It has lost habitat to development and encroachment by exotic, invasive species–such as Daucus carota (Queen Anne’s lace). Additionally, it's so lovely that it has been extensively collected from the wild.

One year I marked the location of several groups of flowering plants so I could easily find them later to collect seed. When I returned to gather seeds, I was surprised I could not find the plants at all! Close inspection revealed the whole colony had been devoured. I’m not sure what mammal dined on them (I'm guessing deer), but hopefully they are an agent to disperse the seed.