Spiranthes diluvialis
Author: Sheviak

Ute ladies' tresses

Orchidaceae (Orchid Family)

Close up of Spiranthes diluvialis by Delia Malone
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Close up of Spiranthes diluvialis by Susan Spackman Panjabi
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Close up of Spiranthes diluvialis by Susan Spackman Panjabi
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Close up of Spiranthes diluvialis by Susan Spackman Panjabi
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Ranks and Status

Global rank: G2G3
State rank: S2
Federal protection status: USFWS Threatened
State protection status: None

[+] Description and Phenology

Artwork in progress by Terry Ruiter. Please also see 1997 profile

General description: Ute Ladies' Tresses is a perennial orchid with usually 1 stem that is 20-50 cm tall and arising from tuberously thickened roots. Its narrow leaves are 1 cm wide, can reach 28 cm long, are longest at their base, and persist during flowering. The inflorescence consists of few to many white or ivory flowers clustered in a spike of 3-rank spirals at the top of the stem. The sepals and petals are ascending or perpendicular to the stem. The lateral sepals often spread abruptly from the base of the flower, and sepals are free or only slightly connate at the base. The lip petal is somewhat constricted at the median.

Look Alikes: Spiranthes romanzoffiana lip petals are deeply constricted in the middle, and have an erose tip; tepals form a hood above the lip, and the inflorescence is densely congested so the rachis is usually not visible (Weber and Wittmann 2012, Ackerfield 2012, Spackman et al. 1997).  Spiranthes romanzoffiana also usually occurs at higher elevations (Spackman et al. 1997).

Phenology: New growth begins in October, remains dormant through the winter. In the spring, the new growth should continue to grow and flower (Coyner 1990). Known to flower between July and September in Colorado, depending on the year (Spackman et al. 1997). 

[+] Habitat

Habitat of Spiranthes diluvialis by Delia Malone
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Habitat of Spiranthes diluvialis by David Anderson
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Along streams and open seepage areas in cottonwoods. Moist meadows at moderate elevations, usually occurring on floodplains in the vicinity of abandoned stream channels and meanders where the vegetation is not too dense or overgrown. Soils are both sandy and stony (Jennings 1989). Subirrigated alluvial soils along streams and in open meadows in floodplains (Spackman et al. 1997).  Associated species include horsetail, milkweed, verbena, lobelia, blue-eyed grass, carpet bentgrass, reed grass, golden rod and canada thistle (Jordan 1992). 


Elevation Range: 4,528 - 7,753 feet (1,380 - 2,363 meters)

[+] Distribution

Distribution of Spiranthes diluvialis in Colorado.
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Colorado endemic: No
Global range: Adapted from Fertig et al. (2005): Known from northern and south-central Utah, central to north-central and northwestern Colorado, east-central and southeastern Wyoming, eastern Idaho, southwestern Montana, eastern Nevada, western Nebraska, and central to north-central Washington, as well as British Columbia, where recently discovered (J. Penny, pers. comm. 2008). Occurs in at least 33 counties in the United States as well as at one site in British Columbia. Utah has the largest number of extant EOs and the highest number of reported plants, followed by Colorado. Using a minimum convex polygon to estimate the range (i.e. without attempting to exclude "extreme discontinuities"), range extent is approximately 915, 850 sq km.
State range: Known from Boulder, Eagle, Garfield, Jefferson, Larimer, and Moffat counties in Colorado. Estimated range is 35,836 square kilometers, calculated in GIS in 2008 by the Colorado Natural Heritage Program by drawing a minimum convex polygon around the known occurrences. Poorly documented historical occurrences in Weld and El Paso counties are not included. Also known from Idaho, Montana, Nebraska, Nevada, Utah, Washington, and Wyoming.

[+] Threats and Management Issues

Summary results of an analysis of the status of Spiranthes diluvialis based on several ranking factors. This species was concluded to be "moderately conserved”. From Rondeau et al. 2011.
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The primary threat at this time is considered to be hydrologic alteration (Rondeau et al. 2011). The species is considered to be threatened throughout its range by many forms of water developments, intense domestic livestock grazing, haying, exotic species invasion, fragmentation and urbanization in particular. Vulnerable in parts of range to loss of pollinators, and control of rodent predators. Seed predation by voles poses a potentially serious threat to long term viability, however, this appears only to be a problem in agricultural areas, not in more pristine riparian areas. Wetland and riparian area modification may threaten the species, or may create new habitat, depending on how it is done. Similarly mowing and burning may be beneficial or detrimental depending on timing, frequency, etc. (Arft 1995).

[+] References

    • Ackerfield, J. 2012. The Flora of Colorado. Colorado State University Herbarium. 433 pp.
    • Albee, B.J., L.M. Shultz, and S. Goodrich. 1988. Atlas of the vascular plants of Utah. Utah Museum Natural History Occasional Publication 7, Salt Lake City, Utah. 670 pp.
    • Arft, A. M. 1995. The genetics, demography, and conservation management of the rare orchid SPIRANTHES DILUVIALIS. Ph.D. dissertation. University of Colorado, Boulder. 170 pp.
    • Arft, A.M. and T. Ranker. 1998. Allopolyploid origin and population genetics of the rare orchid Spiranthes diluvialis. American Journal of Botany 85:110-122.
    • Arft, A.M. and T.A. Ranker. 1993. Population genetics and phylogenetic systematics of the rare orchid Spiranthes diluvialis: implications for conservation.
    • Colorado Native Plant Society. 1989. Rare plants of Colorado. Rocky Mountain Nature Association, Colorado Native Plant Society, Estes Park, Colorado. 73 pp.
    • Coyner, J. 1990. Report for population study: Spiranthes diluvialis. Unpublished report. University of Utah, Salt Lake City, UT.
    • 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.
    • Fertig, W., R. Black, and P. Wolken. 2005. Rangewide status review of Ute Ladies'-Tresses (Spiranthes diluvialis). Prepared for the US Fish and Wildlife Service and Central Utah Water Conservancy District. 30 September 2005. Online. Available: http://www.fws.gov/mountain-prairie/species/plants/uteladiestress/SPDI_Status%20review_Fertig2005.pdf (Accessed 2008).
    • 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.
    • Heidel, B. L. 1998. Conservation status of SPIRANTHES DILUVIALIS Sheviak in Montana. Unpublished report to U.S. Fish & Wildlife Service. Montana Natural Heritage Program, Helena, Montana. 55 pp. + appendices.
    • Jennings, William F. 1989. Final Report Colorado Natural History Small Grants Program Prepared for The Nature Conservancy.
    • Jordan, Lucy. 1992. Listing priority number assignment form, USFWS.
    • 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.
    • Neely, B., S. Panjabi, E. Lane, P. Lewis, C. Dawson, A. Kratz, B. Kurzel, T. Hogan, J. Handwerk, S. Krishnan, J. Neale, and N. Ripley. 2009. Colorado Rare Plant Conservation Strategy, Developed by the Colorado Rare Plant conservation Initiative. The Nature Conservancy, Boulder, Colorado, 117 pp.
    • O'Kane, S. L. 1988. Colorado's Rare Flora. Great Basin Naturalist. 48(4):434-484.
    • Pierson, K., V.J. Tepedino, S. Sipes, and K. Kuta. 2001. Pollination ecology of the rare orchid, Spiranthes diluvialis: Implications for conservation. Pages 153-164 in: J. Maschinski and L. Holter, tech. eds. Southwestern rare and endangered plants: Proceedings of the Third Conference; 2000 September 25-28; Flagstaff, AZ. Proceedings RMRS-P-23. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fort Collins, CO.
    • Rondeau, R., K. Decker, J. Handwerk, J. Siemers, L. Grunau, and C. Pague. 2011. The state of Colorado's biodiversity 2011. Prepared for The Nature Conservancy. Colorado Natural Heritage Program, Colorado State University, Fort Collins, Colorado.
    • 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.
    • Sheviak, C.J. 1984. Spiranthes diluvialis (Orchidaceae); a new species from the western U.S. Brittonia 36(1): 8-14.
    • Sipes, S. D. and V. J. Tepedino. 1995. Reproductive biology of the rare orchid, Spiranthes diluvialis: breeding system, pollination, and implications for conservation. Conservation Biology 9(4):929-938.
    • 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.
    • Szalanski, A.L., G. Steinauer, R. Bischof, and J. Petersen. 2001. Origin and conservation genetics of the Threatened Ute ladies'-tresses, Spiranthes diluvialis (Orchidaceae). American Journal of Botany 88: 177-180.
    • U.S. Fish and Wildlife Service (USFWS). 1992. Endangered and threatened wildlife and plants; final rule to list the plant SPIRANTHES DILUVIALIS (Ute ladies' tresses) as a threatened species. Federal Register 57(12):2048-2054.
    • U.S. Fish and Wildlife Service. 1990. Proposal to list the plant Spiranthes diluvialis (Ute ladies'-tresses) as a threatened species. Federal Register 55(219): 47347-47350.
    • U.S. Fish and Wildlife Service. 1995. Ute ladies' tresses (SPIRANTHES DILUVIALIS) draft recovery plan. U.S. Fish and Wildlife Service, Denver, Colorado. 46 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, Eastern Slope, A Field Guide to the Vascular Plants, Fourth Edition. Boulder, Colorado. 555 pp.
    • 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.
    • Welsh, S.L., N.D. Atwood, S. Goodrich, and L.C. Higgins (eds.) 1993. A Utah flora. 2nd edition. Brigham Young Univ., Provo, Utah. 986 pp.

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