Penstemon mensarum
Author: Pennell

Grand Mesa penstemon

Scrophulariaceae (Figwort Family)

Close up of Penstemon mensarum by Bernadette Kuhn
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Close up of Penstemon mensarum by Peggy Lyon
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Close up of Penstemon mensarum by Lori Brummer
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Taxonomic Comments

Many authors now place this genus in the Plantaginaceae, the Plantain Family (e.g., Ackerifeld 2012).

Ranks and Status

Global rank: G2
State rank: S2
Federal protection status: None
State protection status: None

[+] Description and Phenology

Artwork in progress by Estelle DeRitter

General description: Plants 4-10 dm tall, with one to few, erect stems, glabrous up to the glandular inflorescence.  Leave are entire, glabrous. Basal leaves are long, elliptic.  Cauline leaves are sessile and oblanceolate.  Inflorescence is elongate, slender.  Calyx is glandular pubescent, 3-5 mm long.  Corolla is dark blue or blue tinged with purple, 14-20 mm long, glandular-pubescent externally, glabrous within.  Staminode is included within the corolla throat, and is bearded most of its length.  Anther sacs are short-hairy on the side opposite dehiscence (Harrington 1954; Ackerfield 2012).

Look Alikes: Similar to P. strictus although the corollas are shorter. It is also similar to P. alpinus. The lobes are intermediate between those of P. strictus and P. alpinus, the calyx is covered with a glandular puberulence that extends in a lesser degree to the corolla itself.

Phenology: Flowers in late June through July, and sets fruit in early August (Colorado Natural Heritage Program 2012).

[+] Habitat

Habitat of Penstemon mensarum by Bernadette Kuhn
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Habitat of Penstemon mensarum by Lori Brummer
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Occurs among oaks, aspens, sagebrush, and in meadows; and thrives in disturbed areas along roads and trails (Harrington 1954, Darrow 2006).  Often found in deep clayey loam soils.  Associated species include: Rosa woodsii, Cirsium scariosum, Helianthella quinquenervis, Lupinus argenteus, Festuca thurberi, Ipomopsis aggregata, Geranium viscosissimum, Castilleja linarifolia, Geranium richardsonii, Padus virginiana, Rubus parviflora, Symphoricarpos rotundifolious, Potentilla pulcherrima, and Phacelia sericea.

Elevation Range: 6,670 - 10,200 feet (2,033 - 3,109 meters)

[+] Distribution

Distribution of Penstemon mensarum in Colorado
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Colorado endemic: Yes
Global range: Endemic to Colorado (Delta, Gunnison, Mesa, and Pitkin counties). Roughly 13.400 square km.

[+] Threats and Management Issues

Roads and noxious weeds seem to be the primary concerns for this species but most records do not report threats.

[+] References

    • Ackerfield, J. 2012. The Flora of Colorado. Colorado State University Herbarium. 433 pp.
    • Darrow, K. 2006. Wild About Wildflowers; Extreme Botanizing in Crested Butte, Wildflwer Capital of Colorado. WildKat Publishing Co., Glendale, AZ. 224 pp.
    • Harrington, H.D. 1954. Manual of the plants of Colorado. Sage Press, Chicago. 666 pp.
    • 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.
    • Nold, Robert. 1999. Penstemons. Timber Press, Portland OR. 259 pp.
    • USDA, NRCS. 2013. The PLANTS Database. National Plant Data Team, Greensboro, NC 27401-4901 USA.
    • 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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