Penstemon retrorsus
Author: Payson ex Pennell

Adobe beardtongue

Scrophulariaceae (figwort family)

Close up of Penstemon retrorsus by Lori Brummer.

Close up of Penstemon retrorsus by Barbara Galloway.
Close up of Penstemon retrorsus by Barbara Galloway.

Taxonomic Comments

Weber and Wittmann (2012) lump this taxon with P. caespitosus Nuttall. Ackerfield (2015) recognizes Penstemon retrorsus, and, along with others, place the genus Penstemon in the Plantaginaceae, the Plantain Family.

Ranks and Status

Global rank: G3
State rank: S3
Federal protection status: None
State protection status: None

Description and Phenology

Penstemon retrorsus by Janet Wingate.

General description: Mat forming, erect perennial with small basal leaves.  Stems 1-2 dm tall, cinereous (ashy gray). Leaves entire, cinereous with dense, retrorse pubescence (hairs which point backwards toward the base of the leaves or the stems). Flowering stem erect, greatly exceeding the basal leaves. Calyx cinereous-pubescent, 3-5 mm long.  Corolla bluish-purple, throat flattened and 2 ridged within on lower side. Staminode slender, bearded most of its length, anthers glabrous (Colorado Native Plant Society 1989, Spackman et al. 1997, Ackerfield 2015).

Look Alikes: Distinguished from other species by its mat-forming habit, small basal leaves with dense retrorse pubescence, and specific habitat (Spackman et al. 1997).

Phenology: Flowers from early May until early June, in fruit by mid June (Spackman et al. 1997).


Habitat of Penstemon retrorsus by Barbara Galloway.

Habitat of Penstemon retrorsus by Barbara Galloway.

Habitat of Penstemon retrorsus by Delia Malone.

Barren gray adobe hills of Mancos Formation shale where there is a relatively high amount of moisture (in drainage areas or on the north sides of hills). Clayey, alkaline soils; associated with saltbush and/or sagebrush (Spackman et al. 1997). Additional associated taxa include Gutierrezia, Juniperus, Yucca, and Artemisia.

Elevation Range: 5,381 - 9,071 feet (1,640 - 2,765 meters)


Colorado endemic: Yes
Global range: Colorado endemic growing in a 15 mile long area in the northern fork of the Gunnison Valley and the Uncompahgre River Valley, in Delta and Montrose counties, Colorado.
Distribution of Penstemon retrorsus in Colorado according to mapped land ownership/management boundaries (CNHP 2017, COMaP).

Distribution of Penstemon retrorsus in Colorado.

Threats and Management Issues

Four wheel drive vehicle and motorcycle use on the shale hills is affecting the plant. The plants do seem to be tolerant of intermittent winter sheep grazing. Colorado climate scenarios for 2050 suggest temperature will increase by 3-7 F and precipitation may decrease or increase. The impact to any given rare plant habitat is likely to vary. Long-term monitoring that includes weather and soil moisture data is critical to understanding climate impacts.


    • Beardsley, M. and D. A. Steingraeber. 2013. Population dynamics, rarity and risk of extirpation for populations of Mimulus gemmiparus (budding monkeyflower) on National Forests of Colorado. A research report submitted to the USFS Forest Service. Arapaho and Roosevelt National Forets and Pawnee National Grassland. pp 17. Accessed online on May 11 at: documents/USFS_MimulusStatusReport2013.pdf
    • Colorado Native Plant Society. 1989. Rare plants of Colorado. Rocky Mountain Nature Association, Colorado Native Plant Society, Estes Park, Colorado. 73 pp.
    • Colorado Natural Heritage Program and the Geospatial Centroid. 2017. The Colorado Ownership and Protection Map (COMaP). Colorado State University, Ft. Collins, CO.
    • Harmon, W., B. Johnston, and J.S. Peterson. 1981. Status report on Penstemon retrorsus. Unpublished report prepared for the Colorado Natural Areas Program, Denver, CO.
    • Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
    • O'Kane, S. L. 1988. Colorado's Rare Flora. Great Basin Naturalist. 48(4):434-484.
    • Spackman, S., B. Jennings, J. Coles, C. Dawson, M. Minton, A. Kratz, and C. Spurrier. 1997. Colorado rare plant field guide. Prepared for Bureau of Land Management, U.S. Forest Service and U.S. Fish and Wildlife Service by Colorado Natural Heritage Program.
    • USDA, Natural Resources Conservation Service, PLANTS Database [USDA PLANTS]. Accessed 2017.
    • Weber, W. A. and R. C. Wittmann. 2012. Colorado Flora, Western Slope, A Field Guide to the Vascular Plants, Fourth Edition. Boulder, Colorado. 532 pp.

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