Penstemon davidsonii

Penstemon davidsonii is a species of penstemon known by the common name Davidson's penstemon, honoring Dr. George Davidson. It is native to western North America.

Description
Penstemon davidsonii is a low, mat-forming perennial up to 10 cm tall. The leaves are up to 1.5 cm long, thick and firm, usually glabrous, with entire to serrulate margins. The leaves often have a paler green, tan, or reddish edge. The flowers are tubular, blue-lavender to purple, and large relative to the short stature of the plant. The calyx is covered with short hair. Larger plants often flower abundantly, with the leaf mat nearly covered with the showy flowers.

Taxonomy
Penstemon davidsonii is included in Penstemon subgenus Dasanthera, along with P. barrettiae, P. cardwellii, P. ellipticus, P. fruticosus, P. lyallii, P. montanus, P. newberryi, and P. rupicola.

Names
Penstemon davidsonii is known by several common names. It is occasionally called "Alpine penstemon". The variety Penstemon davidsonii var. davidsonii is commonly called the "timberline penstemon". It shares the name "creeping penstemon" with Penstemon teucrioides.

Distribution and habitat
Penstemon davidsonii is native to North America from the Sierra Nevada Range in California and Nevada through the Coast and Cascade ranges of Oregon and Washington into British Columbia.

It grows on rocks or in rocky soils in sunny mountain locations.

Varieties

 * P. davidsonii var. davidsonii – Davidson's penstemon
 * P. davidsonii var. menziesii (D.D. Keck) Cronquist – Menzies' penstemon
 * P. davidsonii var. praeteritus Cronquist – timberline beardtongue