Hypoxis hirsuta
Author: (L.) Coville

Yellow stargrass

Liliaceae (Lily Family)

Close up of Hypoxis hirsuta by Fred Johnson.
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Close up of Hypoxis hirsuta by Steve Olson.
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Taxonomic Comments

Weber and Wittmann (2012) and Ackerfield (2015) place this species in the Hypoxidaaceae, the Yellow Stargrass or Stargrass Family. Hypoxis hirsuta is the only taxon in this family known from Colorado. Another common name is Common goldstar (Culver and Lemly 2013, Ackerfield 2015).

Ranks and Status

Global rank: G5
State rank: S1
Federal protection status: None
State protection status: None

[+] Description and Phenology

Hypoxis hirsutafrom the USDA-NRCS PLANTS Database, Britton and Brown 1913.
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General description: Herbaceous perennial monocot with 6-merous yellow flowers, and with rhizomes or corms. Plants are scapose (without stem leaves), sparsely to densely pubescent, often pilose (with long, soft hairs), pubescence including at least some irregularly stellate trichomes. Leaves are all basal, grasslike. Plants are up to 3 dm tall with scape shorter than leaves. Tepals 6-10 mm long, yellow; ovary inferior. Fruits are capsules, crowned by persistent flower parts; seeds black, lustrous, 1-1.5 mm, coarsely rough (Weber and Wittmann 2012, Culver and Lemly 2013, Ackerfield 2015).

Look Alikes: Not likely to be confused with other taxa in similar habitats. The combination of all basal leaves, yellow tepals, and inferior ovary is distinctive.

Phenology: Flowers and fruit April-July.

[+] Herbarium Photos

Images of Hypoxis hirsuta housed at the Colorado State University Herbarium.

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[+] Habitat

Habitat of Hypoxis hirsuta by Denise Culver.
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In Colorado, Hypoxis hirsuta has been found in moist meadows, seeps, and fens associated with blue spruce, river birch, willows, sedges, rushes, and/or grasses. Plants have been found growing in peat with sandy gravel and alluvium (Colorado Natural Heritage Program occurrence records 2017). Additional information is needed to better describe the habitat for this species in Colorado.

Elevation Range: 5,069 - 8,451 feet (1,545 - 2,576 meters)

[+] Distribution

Distribution of Hypoxis hirsuta in Colorado according to mapped land ownership/management boundaries (CNHP 2017, COMaP).
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Distribution of Hypoxis hirsuta in Colorado.
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Colorado endemic: No
Global range: Central, midwestern, and eastern US, and north into Canada (USDA NRCS 2017). Known from Saskatchewan to New Mexico east to the east coast (except Florida) (Flora of North America 2002; NatureServe Network Database as of February 2017).  A tallgrass prairie relict (Weber and Wittmann 2012, Culver and Lemly 2013).
State range: In Colorado, this species has been documented in Denver, Custer, El Paso, and Las Animas counties (Culver and Lemly 2013, Ackerfield 2015, Colorado Natural Heritage Program occurrence records as of 2017).


[+] Threats and Management Issues

The predominant land use around the Colorado occurrences appears to be cattle grazing. Elk and other wildlife species may also reside in the habitat.  Incompatible grazing has not been documented, but monitoring is warranted to help assure this does not become an issue given the very small population size. Water sources must be protected to ensure long-term viability. 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.

[+] References

    • Brackett. 1923. American Species of Hypoxis.
    • Britton, N. L. and A. Brown. 1913. An Illustrated Flora of the Northern United States and Canada. 3 vol. Dover Publications, Inc., N. Y. 2052 pp.
    • Colorado Natural Heritage Program and the Geospatial Centroid. 2017. The Colorado Ownership and Protection Map (COMaP). Colorado State University, Ft. Collins, CO.
    • Culver, D.R. and J.M. Lemly. 2013. Field Guide to Colorado's Wetland Plants; Identification, Ecology and Conservation. Colorado Natural Heritage Program, Colorado State University, Fort Collins, 694 pp.
    • Flora of North America Editorial Committee. 2002. Flora of North America North of Mexico. Vol. 26. Magnoliophyta: Liliidae: Liliales and Orchidales. Oxford Univ. Press, New York. xxvi + 723 pp.
    • Great Plains Flora Association. 1986. Flora of the Great Plains. University Press of Kansas, Lawrence, KS. 1402 pp.
    • Jennings, W.F. 1989. Final report for Eustoma grandiflorum, Spiranthes diluvialis, Malaxis brachypoda, Hypoxis hirsuta, Physaria bellii, and Aletes humilis. Unpublished report prepared for the Nature Conservancy, 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.
    • USDA, Natural Resources Conservation Service, PLANTS Database [USDA PLANTS]. http://plants.usda.gov/. Accessed 2017.
    • 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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