Ute ladies'-tresses (Spiranthes diluvialis)

Federal Register | Recovery | Critical Habitat | Conservation Plans | Petitions | Life History

Listing Status:   


General Information

Ute ladiesí-tresses is a perennial herb with erect, glandular-pubescent stems 12-60 cm tall arising from tuberous-thickened roots. Basal leaves are narrowly linear, up to 1 cm wide and 28 cm long, and persist at the time of flowering. Leaves become progressively smaller up the stem and are alternate. The inflorescence is a sparsely pubescent 3-15 cm long spike of numerous small white or ivory-colored flowers arranged in a gradual spiral. Individual flowers are 7.5-15 mm long and faintly fragrant (with a vanilla-like scent). The lip petal is oval to lance-shaped, narrowed at the middle, and has crispy-wavy margins. Sepals are separate or fused only at the base (not fused into a hood-like structure) and are often spreading at their tips. Fruits are cylindric capsules with numerous seeds. The species occurs in Colorado, Idaho, Montana, Nebraska, Nevada, Utah, Washington, and Wyoming.

  • States/US Territories in which the Ute ladies'-tresses, Wherever found is known to or is believed to occur:  Colorado , Idaho , Montana , Nebraska , Nevada , Utah , Washington , Wyoming
  • US Counties in which the Ute ladies'-tresses, Wherever found is known to or is believed to occur:  View All
  • USFWS Refuges in which the Ute ladies'-tresses, Wherever found is known to occur:  Browns Park National Wildlife Refuge
  • Countries in which the the Ute ladies'-tresses, Wherever found is known to occur:  United States
Current Listing Status Summary
Status Date Listed Lead Region Where Listed
1992-01-17 Mountain-Prairie Region (Region 6) Wherever found

» Federal Register Documents

Federal Register Documents
Date Citation Page Title
1992-01-17 00:00:00.0 57 FR 2048 205 ETWP; Final Rule to List the Plant Spiranthes diluvialis, Ute Ladies'- Tresses, as a Threatened Species
1990-11-13 00:00:00.0 55 FR 47347 47350 ETWP; Proposal to List the Plant Spiranthes diluvialis (Ute ladies'- tresses) as a Threatened Species; 55 FR 47347 47350
2004-10-12 00:00:00.0 69 FR 60605 60607 90-Day Finding on a Petition To Delist the Ute Ladies'-Tresses Orchid and Initiation of a 5-Year Review

» Recovery

Current Recovery Plan(s)
Date Title Plan Action Status Plan Status
1995-09-21 Ute Ladies'-Tresses Draft Recovery Plan View Implementation Progress Draft
Other Recovery Documents
Date Citation Page Title Document Type
2004-10-12 69 FR 60605 60607 90-Day Finding on a Petition To Delist the Ute Ladies'-Tresses Orchid and Initiation of a 5-Year Review
  • Notice 5-year Review
  • Notice 90-day Petition Finding, Substantial

» Critical Habitat

No critical habitat rules have been published for the Ute ladies'-tresses.

» Conservation Plans

No conservation plans have been created for Ute ladies'-tresses.

» Petitions

» Life History

Habitat Requirements

When Ute ladiesí-tresses was listed in 1992 it was known primarily from moist meadows associated with perennial stream terraces, floodplains, and oxbows at elevations between 4300-6850 feet (1310-2090 meters). Surveys since 1992 have expanded the number of vegetation and hydrology types occupied by Ute ladiesí-tresses to include seasonally flooded river terraces, subirrigated or spring-fed abandoned stream channels and valleys, and lakeshores. In addition, 26 populations have been discovered along irrigation canals, berms, levees, irrigated meadows, excavated gravel pits, roadside barrow pits, reservoirs, and other human-modified wetlands. New surveys have also expanded the elevational range of the species from 720-1830 feet (220-558 meters) in Washington to 7000 feet (2134 meters) in northern Utah. Over one-third of all known Ute ladiesí-tresses populations are found on alluvial banks, point bars, floodplains, or ox-bows associated with perennial streams.

Food Habits


Movement / Home Range


Reproductive Strategy

Spiranthes diluvialis is a long-lived perennial forb that probably reproduces exclusively by seed. The occasional presence of clustered plants could be the result of asexual reproduction from a single root mass or broken root segment. Such clusters could also be from seed caches or germination of seed from an entire buried fruiting capsule. The life cycle of S. diluvialis consists of four main stages: seedling, dormant, vegetative, and reproductive (flowering or fruiting). Fruits are produced in late August or September across most of the plantís range, with seeds shed shortly thereafter. As with other orchid species, Ute ladiesí-tresses seeds are microscopic, dust-like, and readily dispersed by wind or water. Because of their minute size, Spiranthes seeds contain little stored food to sustain embryos and are probably short-lived in the soil. Recent attempts to germinate S. diluvialis seeds in lab culture found it took up to 1.5 years for germination to occur. It is hypothesized that germinated seedlings must quickly establish a symbiotic relationship with mycorrhizal soil fungi in order to survive. The absence or rarity of appropriate fungal symbionts in the soil may be a major factor limiting the establishment of new Ute ladiesí- tresses populations. New vegetative shoots are produced in October and persist through the winter as small rosette. These resume growth in the spring and develop into short-stemmed, leafy, photosynthetic plants. Depending on site productivity and conditions, vegetative shoots may remain in this state all summer or develop inflorescences. Vegetative individuals die back in the winter to subterranean roots or persist as winter rosettes. Across its range Spiranthes diluvialis blooms from early July to late October. Flowering typically occurs earlier in sites that have an open canopy and later in well-shaded sites. Bees are the primary pollinators of Ute ladiesí-tresses, particularly solitary bees in the genus Anthophora, bumblebees (genus Bombus), and occasionally non-native honeybees (Apis mellifera). Of these species, Anthophora terminalis is apparently the most effective pollinator. Studies along the Diamond Fork watershed in Utah indicate that orchids pollinated by A. terminalis produce three times as many fruits as plants from Browns Park pollinated only by Bombus species. Long-term monitoring studies indicate that the relative abundance and composition of the available bee fauna varies from year to year, which may impact overall fruit production rates. Other insect taxa (including Syrphid flies, skippers, and other hymenopteran genera) have been observed visiting S. diluvialis blooms for nectar but are too small or improperly shaped to function as pollen vectors.


In 1992, the US Fish and Wildlife Service identified habitat loss and modification (through urbanization, water development, and conversion of wetlands to agriculture), overcollection, competition from exotic weeds, and herbicides as the main current and potential threats to the long term survival of Ute ladiesí-tresses. Since 1992, other threats have been identified including impacts from recreation; mowing for hay production, (mowing, especially in conjunction with winter grazing, can have positive effects on Ute ladiesí-tresses by reducing competing vegetative cover and protective cover for voles); grazing by cattle or horses; hydrology change (modification of wetland habitats through development, flood control, de-watering, and other changes to hydrology); herbivory by native wildlife (particularly voles); reduction in the number and diversity of insect pollinators; drought; absence or rarity of mycorrhizal symbionts; and conflicting management with other rare species.

» Other Resources

NatureServe Explorer Species Reports -- NatureServe Explorer is a source for authoritative conservation information on more than 50,000 plants, animals and ecological communtities of the U.S and Canada. NatureServe Explorer provides in-depth information on rare and endangered species, but includes common plants and animals too. NatureServe Explorer is a product of NatureServe in collaboration with the Natural Heritage Network.

ITIS Reports -- ITIS (the Integrated Taxonomic Information System) is a source for authoritative taxonomic information on plants, animals, fungi, and microbes of North America and the world.

FWS Digital Media Library -- The U.S. Fish and Wildlife Service's National Digital Library is a searchable collection of selected images, historical artifacts, audio clips, publications, and video.