Penstemon hallii
Penstemon hallii, commonly Hall's penstemon or Halls alpine penstemon, is an alpine plant that is native to just the Southern Rocky Mountains of Colorado. It has showy flowers in shades of blue or purple the appear in summer.
Description
Hall's penstemon is modest sized plant with stems that are tall, but most often. It is relatively long-lived for a penstemon with somewhat woody bases to its stems. The stems can grow straight upward or outward before curving to upright and might have glandular hairs towards the ends, but are otherwise hairless and not glaucus. At times the plant will grow into a mat.The basal leaves, those growing directly from the base of the plant, might be smaller or missing entirely, but also can be noticeably larger than those higher up on the plant. The basal leaves and the lower leaves on the stems measure 1.6–8.5 cm long and just 3–9 millimeters wide. They are spatulate to lanceolate, shaped like a spoon or the head of spear, with a tapering base. The tip of the leaves is variable, rounded, with a wide point, or a narrow one, and have no teeth on the edges. Each stem has two to four pairs of leaves attached on opposite sides. The upper ones measure 2.4–5.5 cm long and 2–5 mm wide. All the leaves are hairless except for -scabrous edges, hairs that are rough and point upwards or forwards.
Blooming occurs in the months of July and August. The inflorescence is the upper part of each stem and is normally 2–7 cm, but can be as short as 1 cm. Many sources state that the flowers all face in one direction, however in the Flora of North America it is reported that the flowers can face in all directions. The flowers are in one to seven groups, formally called, with two paired attachment points. Each of the attachment points can have one to four flowers.
The flowers are variable in color, reddish-purple, lilac, somewhat pink, or pale blue, with reddish-purple floral guide lines and sticky glandular hairs on the exterior. They resemble two lipped bell flowers with their abruptly inflated throats. Overall they measure 1.4–2.5 cm long with the mouth having a diameter of 6–7 mm. The stamens do not extend out of the flower, but the sterile staminode often often extends out of the mouth, with a length of 10–15 mm. The staminode is moderately to densely covered in golden-yellow hairs.
The fruit is a capsule that is 6–9 mm long and 4–7 mm wide.
The flowers resemble those of grayleaf creeping penstemon, another Colorado mountain penstemon species. However, it generally is found under timberline and has hairy, but not glandular, leaves and stems unlike the nearly hairless leaves of Hall's penstemon.
Taxonomy
In 1862 Penstemon hallii was scientifically described and named by botanist Asa Gray. It is classified in the Penstemon genus within the family Plantaginaceae. It has one heterotypic synonym, Penstemon bakeri, which was named in 1901 by Edward Lee Greene. It has no accepted varieties. According to a study of Penstemon genetics published in 2016 it is part of a small group of closely related species including upland penstemon and Penstemon mensarum.Names
Penstemon hallii was named for Elihu Hall, a professional botanical collector who arrived in Colorado in 1862 with Asa Gray who named the species for him, though in first publication the genus was spelled Pentstemon. It is known by several related common names including Hall's penstemon, Halls alpine penstemon, Hall's beardtongue, and Hall's alpine beardtongue.Range and habitat
Hall's penstemon is endemic to the state of Colorado. It grows in the high mountains of central Colorado as far as Jackson County in the north of the state southwards nearly to New Mexico in Conejos and Archuleta counties. They are found at elevations of.The species is limited to areas of rock or gravel from just under timberline up into the alpine tundra. They might be found in meadows, on rocky slopes, and along ridges.