Penstemon rydbergii var. aggregatus
Brittonia 31: 106. 1979.
Stems ± retrorsely hairy. Thyrses: axis glabrous or retrorsely hairy; proximal bract margins entire. Flowers: calyx lobes (4.5–) 5–8 × 1.5–2.5 mm, margins erose, rarely lacerate, narrowly to broadly scarious, apex acute to acuminate; corolla (10–) 13–20 mm; pollen-sacs (0.6–) 0.8–1.1 mm. 2n = 32.
Phenology: Flowering Jun–Aug.
Habitat: Sagebrush shrublands, aspen woodlands.
Elevation: 1800–3200 m.
Ariz., Colo., Idaho, Mont., Utah, Wyo.
Variety aggregatus is known from the Rocky Mountains from central Idaho and western Montana to north-central and western Wyoming, north-central Colorado, and central Utah. The variety is sympatric with var. rydbergii in north-central Colorado and south-central Wyoming; some plants from that area are difficult to assign to variety with confidence.
"/4+timescorollathroat" is not declared as a valid unit of measurement for this property.