Frasera coloradensis
Author: (Rogers) D.M. Post

Colorado green gentian

Gentianaceae (Gentian Family)

Close up of Frasera coloradensis by Jill Handwerk
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Close up of Frasera coloradensis by Jill Handwerk
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Ranks and Status

Global rank: G2G3
State rank: S2S3
Federal protection status: None
State protection status: None

[+] Description and Phenology

Frasera coloradensis by Patricia Whalen
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General description: A small (10-20 cm) and variously branched perennial.  Leaves are thick, long and narrow, with white margins, glabrous or minutely pubescent.  Plants apprear as rosettes before flowers are produced.  Flowering structures are typically much branched, with greenish-white flowers.  Calyx is deeply 4-parted, with petals 8-10 mm long.  A small greenish gland occurs near the base of each petal, and small purplish dots appear on the upper surface of the petals (Naumann 1991, Spackman et al. 1997).

Look Alikes: It is quite distinctive and is unlikely to be confused with other taxa (Naumann 1991). However, leaves look superficially like the young leaves of Yucca glauca, but on close inspection, Yucca leaves are thicker and more fibrous, with fibers peeling off at the margins.

Phenology: Flowers in mid-June to mid-July. Produces fruits in July after flowering.

[+] Habitat

Habitat of Frasera coloradensis by Jill Handwerk
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Habitat of Frasera coloradensis by Jill Handwerk
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Habitat of Frasera coloradensis by Steve Olson
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Low sandy/sandstone breaks in grasslands, northerly aspects in between rocks or just below them; shallow slopes. Associated with surface outcrops or shallow-to-bedrock occurrences of Cretaceous rock formations, including Greenhorn limestone, Graneros shale and Dakota sandstone. Plant community generally shortgrass prairie, mixed prairie breaks, or open pinyon-juniper woodlands. Substrate is the best indicator for locations of this species (Naumann 1991, Spackman et al. 1997).

Elevation Range: 4,071 - 5,800 feet (1,241 - 1,768 meters)

[+] Distribution

Distribution of Frasera coloradensis in Colorado
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Colorado endemic: Yes
Global range: Colorado endemic; documented habitat less than 300 acres; potential undocumented habitat is estimated at about 1,000 acres (Naumann 1991). Total range is about 25 miles x 75 miles (estimated by the Colorado Natural Heritage Program in 2008). This species is known from four counties: Baca, Bent, Prowers, and Las Animas.

[+] Threats and Management Issues

Primarily threatened by wind energy development (pers. comm. Don Hazlett 2014). Moderately threatened by agricultural and road management practices such as herbicide application; grazing may suppress reproduction, but probably doesn't frequently kill established plants except in cases of overgrazing; primary threat is inadvertent loss or alteration of naturally limited habitat (Naumann 1991).

[+] References

    • Ackerfield, J. 2012. The Flora of Colorado. Colorado State University Herbarium. 433 pp.
    • Colorado Native Plant Society. 1989. Rare plants of Colorado. Rocky Mountain Nature Association, Colorado Native Plant Society, Estes Park, Colorado. 73 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.
    • Locklear, J. 1989. Plight of the Colorado gentian. Bulletin Board 4(1): 55.
    • Naumann, T.S. 1991. Status Report for Frasera coloradensis. Unpublished report prepared for the Colorado Natural Areas Program, Denver, CO.
    • Rocky Mountain Society of Botanical Artists. 2009. RARE Imperiled Plants of Colorado, a traveling art exhibition. Exhibition catalogue developed by the Denver Botanic Gardens and Steamboat Art Museum.
    • Ryke, N., D. Winters, L. McMartin and S. Vest. 1994. Threatened, Endangered and Sensitive Species of the Pike and San Isabel National Forests and Comanche and Cimarron National Grasslands. May 25, 1994.
    • 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, 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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