Potentilla ambigens
Author: Greene

Southern Rocky Mountain cinquefoil

Rosaceae (Rose Family)

Close up of Potentilla ambigens by Rich Scully
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Close up of Potentilla ambigens flowers by Scott Smith
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Close up of Potentilla ambigens leaves by Rich Scully
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Ranks and Status

Global rank: G3
State rank: S2
Federal protection status: None
State protection status: None

[+] Description and Phenology

Potentilla ambigens: by Sharon Garrett.
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General description: Potentilla ambigens is a taprooted perennial with several stems emerging from a stout rootstock. Potentilla ambigens has large leaves that are borne basally and on the stems. The leaves are two or more decimeters in length and have 9 to 15 leaflets. It has flowers (that are not numerous) with yellow petals that are slightly longer than the sepals, as is typical in Potentilla (Anderson 2006; Colorado Native Plant Society 1997).

Look Alikes: Potentilla ambigens is most commonly mistaken for P. hippiana. The two species are found in similar habitats and have been documented together in Colorado. Potentilla ambigens is taller and more stout, reaching up to 70 cm. in height (Weber and Wittmann 2012, Anderson 2006, Harrington 1954). Potentilla ambigens also differs from P. hippiana in having a densely pilose leaf rachis (pers. comm. Rich Scully).

Phenology: Flowers in June to late July, produces fruits in August (Anderson 2006, Colorado Natural Heritage Program 2012).

[+] Herbarium Photos

Images of Potentilla ambigens housed at the Colorado State University Herbarium.

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[+] Habitat

Habitat of Potentilla ambigens by Rich Scully
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Most Colorado occurrences are on grassy or colluvial slopes, but it may also occur in montane woods. Some sites where Potentilla ambigens is found have been heavily altered by human activities, such as roadsides. Potentilla ambigens is often reported from ecotonal sites at the edges of relatively discrete vegetation types. It is commonly near, but not in, forests dominated by Pinus ponderosa (ponderosa pine). These sites are typically open or in partial shade. However, most reports are from sites where plants are in full sun such as meadows or grasslands. Potentilla ambigens has been reported mainly from flat sites, but it may also grow on gentle hillsides and slopes with up to 30 percent gradient. If on a slope, the site usually has a source of water upslope that increases soil moisture. Potentilla ambigens is not endemic to a particular geologic stratum. Potentilla ambigens is typically found in soils that are either alluvial or colluvial. All reports of soil texture where P. ambigens is found note the presence of coarse-textured, often gravelly soils. Potentilla ambigens is associated with several coniferous forest types. These include ponderosa pine woodlands, ponderosa pine savannas, and mixed coniferous forests (Anderson 2006, Colorado Natural Heritage Program 2012).

Elevation Range: 6,608 - 9,062 feet (2,014 - 2,762 meters)

[+] Distribution

Distribution of Potentilla ambigens in Colorado according to mapped land ownership/management boundaries (CNHP 2012, COMaP v9 ).
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Distribution of Potentilla ambigens in Colorado
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Colorado endemic: No
Global range: Potentilla ambigens is distributed in 44 occurrences across 17 counties in Wyoming, Colorado, and New Mexico. Most of the population probably occurs in New Mexico, but the overall distribution of this species is poorly understood (Anderson 2006).
State range: In Colorado, Potentilla ambigens is known from five counties: El Paso, Jefferson, Larimer, Mineral, and Saguache (Anderson 2006, Colorado Natural Heritage Program 2012).

[+] Threats and Management Issues

Observations and quantitative data indicate several threats to the persistence of Potentilla ambigens. In order of decreasing priority, these threats include off-road vehicle and other recreational use; residential and commercial development; the secondary impacts of grazing, roads, and water development; exotic species invasion; altered fire regime; global climate change; and pollution. Not every threat affects every site, and some threats are more immediate than others. Because many occurrences are represented by few individuals, they may also be threatened by the effects of small population size and stochastic events (Anderson 2006).

[+] References

    • Ackerfield, J. 2012. The Flora of Colorado. Colorado State University Herbarium. 433 pp.
    • Colorado Natural Heritage Program. 2012. Biodiversity Tracking and Conservation System. Colorado State University, Fort Collins, CO.
    • Flora of North America Editorial Committee. 2014. Flora of North America North of Mexico. Vol. 9. Magnoliophyta: Picramniaceae to Rosaceae. Oxford University Press, New York. xxiv + 713 pp.
    • Harrington, H.D. 1954. Manual of the plants of Colorado. Sage Press, Chicago. 666 pp.
    • Heil, K.D., S.L. O'Kane Jr., L.M. Reeves, and A. Clifford, 2013. Flora of the Four Corners Region, Vascular Plants of the San Juan River Drainage; Arizona, Colorado, New Mexico, and Utah. Missouri Botanical Garden Press, St. Louis, Missouri. 1098 pp.
    • Johnston, B.C. 1980. Studies of population variability leading to a new classification of Potentilla sect. Multijugae (Rosaceae). MS Thesis, University of Colorado, Boulder, 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.
    • Lavender, A.E., M.M. Fink, S.E. Linn, D.M. Theobald. 2011. Colorado Ownership, Management, and Protection v9 Database. Colorado Natural Heritage Program and Geospatial Centroid, Colorado State University, Fort Collins, CO. (30 September).
    • 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, Eastern Slope, A Field Guide to the Vascular Plants, Fourth Edition. Boulder, Colorado. 555 pp.

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