Narrowleaf Penstemon - Penstemon angustifolius
State Rank Reason (see State Rank above)
Over a dozen, small extant and/or presumed extant occurrences are known in southeast Montana, plus a few historical collections from the same area. Only one of the known populations appears to be relatively large. Additional suitable, but unsurveyed habitat likely exists in eastern Montana.
- Details on Status Ranking and Review
Score2-3 - Very Small to Small: Population size is imprecisely known but is believed to be <10,000 individuals.
CommentMost occurrences are reported to have only a few plants up to a maximum of several dozen plants observed. The species was reported to be common at a few additional sites.
Score1-2 - Sporadic Distribution/Regional Endemic: Species is limited in distribution but is either too poorly documented or the information to precisely categorize it was lacking at the time its status was reviewed.
Area of Occupancy
Score2 - Low: Generally occurring in 4-10 Subwatersheds (6th Code HUC’s).
Score1-2 - Moderate to High.
CommentSandy soils, particulary in sandy blowouts.
ScoreNA - Rank factor not assessed.
Score0-1 - Low to Medium.
Score1 - Moderate Vulnerability: Specific biological attributes, unusual life history characteristics or limited reproductive potential makes the species susceptible to extirpation from stochastic events or other adverse impacts to its habitat and slow to recover.
Raw Conservation Status Score
7 to 11 total points scored out of a possible 16 (Rarity factors and threats only).
Narrowleaf Penstemon is a perennial herb with usually 1 erect stem 15-45 cm tall which arises from a taproot surmounted by a branched, woody crown. Basal leaves are 4-9 cm long and strap or narrowly lance-shaped with short petioles and entire margins. The opposite stem leaves are just as long but lack petioles. Foliage is glabrous, somewhat thickish, and often covered with a thin coat of bluish wax. The inflorescence consists of clusters of several short-stalked flowers in the axils of the reduced upper leaves. The tubular corolla is flared and 2-lipped at the mouth, 14-20 (23) mm long, and pink to lavender or bright blue, and glabrous externally. The 5 narrowly lance-shaped sepals are 4-8 mm long and have a narrow white margin. The 4 anthers are glabrous.
Our plants are variety angustifolius.
Flowering in May-June.
The only other Penstemons in eastern Montana with a glabrous corollas are P. nitidus and P. grandiflorus but neither have linear leaves.
Great Plains, from ND to MT, and south from OK to AZ. Peripheral.
Observations in Montana Natural Heritage Program Database
Number of Observations:
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Map Help and Descriptions
(Observations spanning multiple months or years are excluded from time charts)
Sandy-soiled, prairie grasslands on hills and slopes. Plants are often most abundant on sandy blowouts and other sparsely-vegetated areas. Common associated species include Andropogon scoparius, Bouteloua gracilis, Carex filifolia, Stipa comata, Calamovilfa longifolia, Tradescantia occidentalis, Artemisia campestris, Artemisia frigida, Heterotheca villosa, Helianthus rigidus and Yucca glauca.
Ecological Systems Associated with this Species
- Commonly Associated with these Ecological Systems
Penstemon angustifolius is a short-lived perennial.
- Additional ReferencesLegend: View Online Publication
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- Heidel, B.L. and K.H. Dueholm. 1995. Sensitive plant survey in the Sioux District, Custer National Forest, 1994, Carter County, Montana and Harding County, South Dakota. Unpublished report to the Custer National Forest. Montana Natural Heritage Program, Helena, Montana. 95 pp. plus appendices.
- Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
- Strickler, D. 1997. Northwest penstemons. Flower Press, Columbia Falls, Montana. 191 pages.
- Vanderhorst, J.P., S.V. Cooper, and B.L. Heidel. 1998. Botanical and vegetation survey of Carter County, Montana. Unpublished report prepared for the Bureau of Land Management. Montana Natural Heritage Program, Helena. 116 pp. + app.