Appreciating penstemons at a rather different level than usual, here are some close-ups of the flowers of Penstemon venustus, showing some of the identifying features, as referenced from Lodewick and Lodewick (Key to the Genus Penstemon).
The stamen filaments are hairy just below the anther*:
*Apparently, this is the only Penstemon species to show this (ref. Lodewick and Lodewick).
The anther sacs are also slightly pubescent with long hairs.
Anthers are exerted (they extend past the flower tube, and are visible when the flower is held in side view, bottom of photo); corolla up to 4 cm (these measure 4 cm):
Corolla lobes are ciliate (having a marginal fringe of minute hairs)
The anther sacs are "bag-shaped" or "sack-shaped" (re. Lodewick and Lodewick), or horseshoe-shaped (according to another reference). Horseshoe-shaped seems like an apt description, to me. The staminode is bearded.