Penstemon virgatus or Penstemon unilateralis
(One-sided Penstemon)
Scrophulariaceae (Figwort)
Penstemon unilateralis is a tall plant with blossoms concentrated on one side of the stem, as described by the species name unilateralis. Leaves are long and narrow. The staminode, or non-functional stamen, of P. unilateralis is white and hairless.

Compare to Penstemon secundiflorus, which also has flowers toward one side of the stem. P. secundiflorus has a hairy staminode and broader, grayer leaves.

Vegetation zone:  Foothills, Montane
Time of bloom:  June - July
Origin:  Native
Eastern Colorado Wildflowers