CPC National Collection Plant Profile

Eriogonum ovalifolium var. williamsiae

James D. Morefield

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CPC National Collection Plant Profile

Eriogonum ovalifolium var. williamsiae

Common Names: 
steamboat buckwheat, wild buckwheat, William's buckwheat
Growth Habit: 
Subshrub, Forb/herb
CPC Number: 


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 Fish & WildLife

Eriogonum ovalifolium var. williamsiaeenlarge
Photographer: James D. Morefield
Image Owner: Nevada Natural Heritage Program

Eriogonum ovalifolium var. williamsiaeenlarge
Photographer: James D. Morefield
Image Owner: Nevada Natural Heritage Program

Eriogonum ovalifolium var. williamsiae is Fully Sponsored
Primary custodian for this plant in the CPC National Collection of Endangered Plants is: 
Edward Guerrant, Ph.D. contributed to this Plant Profile.

Eriogonum ovalifolium var. williamsiae

Extreme habitat specificity limits Steamboat buckwheat to less than 250 acres in Nevada. Here it grows in the forbidding conditions surrounding thermal Hot Springs. This is the sole location of this endangered plant in the entire world. It is listed as Endangered by the U.S. Fish and Wildlife Service and as Critically endangered by the state of Nevada.

Steamboat buckwheat grows near hot springs, which humans have tapped as a geothermal energy resource. The fate of this rare species was, fortunately, considered during recent development. In order to avoid negatively affecting this sole population during the construction of a geothermal power plant, a management plan was constructed to minimize the effect on the buckwheat. Additionally, a biologist was on site to monitor any impact of construction.

Plants that have limited ranges are generally characterized by low genetic diversity. Steamboat buckwheat is an exception; genetic analysis reveals that this rare species is as diverse as many widespread plants. The conservation of this plant species in important so that this genetic diversity can be maintained. Due to its limited and specific habitat, establishing new populations is not a viable option. Instead, the conservation focus should be on maintaining population numbers and limiting population fragmentation to maintain diversity by preventing inbreeding.

Distribution & Occurrence

State Range
State Range of  Eriogonum ovalifolium var. williamsiae
  Open areas with sparse vegetation, in gravelly, sandy-clay dry soils derived from hot spring deposits. Specifically, siliceous opaline sinter precipitated by past thermal spring flows, but not near surface water. Some root in hard, rock-like deposits (Williams 1982, NNHP 2001).
Associated species include Atriplex confertifolia, Sarcobatus vermiculatus, Chrysothamnus nauseosus, Gutierrezia sarothrae, and Artemisia tridentata (Williams 1982, NNHP 2001).
Elevation 4565 to 4720 ft (1390-1440 m) (Williams 1982, NNHP 2001)

  Localized near a hot springs in western Nevada.

Number Left
  As of 2000: 1 population composed of 3 sub-populations over an area of 100-150 acres (Archibald et al. 2001) with a total estimated population of 200,000 individuals (NNHP 2001).


Global Rank:  
Guide to Global Ranks
Federal Status:  
Guide to Federal Status
Recovery Plan:  

State/Area Protection
  State/Area Rank Status Date  
  Nevada S1 CE 3/30/2001  

Conservation, Ecology & Research

Ecological Relationships
  Eriogonum ovalifolium var williamsiae reproduces by seed and vegetative spread. Flowers are visited by a diverse group of smallish insects including bees, wasps, flies, and butterflies (Archibald et al. 2001). Some observers have suggested that butterflies pollinate them and that ants disperse the seeds (Soper 1987). The plant can spread clonally by rhizomes, so individual genets are difficult to distinguish (Knight 1993). It is gynodioecious. Male sterile, or female plants produce flowers whose stamens bear anthers that are either small, poorly developed and knob-like, or larger but flattened; neither type produces pollen. The flowers of hermaphroditic plants produce normal, plump anthers that produce pollen. These flowers are self-compatible, but require a pollinator (Archibald et al. 2001).

Rare, geographically confined species are often suspected of being genetically impoverished-having low estimates of genetic variation. In contrast, Eriogonum ovalifolium var. williamsiae had high values for all three estimates of genetic variation comparable to more widespread species. Two possible explanations for this high level of variation include either hybridization with another related taxa, or a recent speciation event via hybridization of two or more widespread taxa (Archibald et al. 2001). The gynodioecious breeding system may be involved in maintaining high variation because it promotes out-crossing (Archibald et al. 2001). Like many apparent hybrids, E. ovalifolium var williamsiae is confined to a unique habitat that greatly differs from that of its hypothesized parents: E. o. var. ovalifolium is found on dry sand or gravel and E. o. var. eximium is found on granitic sand. Eriogonum ovalfolium var. williamsiae, produces viable seed at a very low rate (<1%), further evidence suggesting that this may be a hybrid species (Archibald et al. 2001).

  Although locally abundant, only a few small areas of habitat (Williams 1982).
Vehicular traffic, recreation (Williams 1982).
Garbage dumping (Williams 1982).
Nearby geothermal drilling and other water diversions may change ground water supply (Williams 1982 and NNHP 2001).
Construction of geothermal power plant (Nelson 1991).
Expansion of US Interstate Highway as plants are found along the highway right-of-way (Archibald et al. 2001).
Competition with tall whitetop (Lepidium latifolium) and other invasive weeds (NNHP 2001).

Current Research Summary
  Genetic diversity studies utilizing allozymes revealed that, in contrast to many endemics, Steamboat buckwheat has high levels of genetic variation. Researchers also discovered that it is genetically similar to the widespread Eriogonum ovalifolium var. ovalifolium (Archibald et al. 2001).
Determination of extent of clonality utilizing allozymes found clones as far as 67 cm away from each other. The frequency of clonal growth was not determined (Archibald et al. 2001).
There was no evidence of inbreeding utilizing allozymes analysis (Archibald et al. 2001).
Germination trials revealed a preference for cold stratification and alternating temperatures. 100% of seeds germinated when subjected to 8 weeks of cold stratification followed by alternating 50F/68F (10/20C) temperatures. 67% germinated under constant 68F (20C) temperatures following cold stratification. Without cold stratification, 86% of seeds in the alternating temperature treatment germinated while 83% of seeds in constant temperatures germinated (BBG File).

Current Management Summary
  Guidelines established to minimize impact of power plant construction on plant populations were implemented in 1991 (Nelson 1991). This management plan is scheduled to continue for a 30-year duration (Knight 1993).
Transplantation of all potentially effected plants was completed prior to initiation of power plant construction (Knight 1993). However, there was only a 25% survival rate (Archibald et al. 2001).
Seeds stored at The Berry Botanic Garden.

Research Management Needs
  Limiting population fragmentation is necessary to maintain gene flow of this highly diverse species, decreasing inbreeding and genetic drift. Care should be taken in the construction of roads or new geothermal facilities to avoid population areas and minimize the impact of construction (Archibald et al. 2001).
Further genetic studies to compare nuclear and cytoplasmic DNA among varieties of Eriogonum ovalifolium. Chromosomal information (number and size of chromosomes).
Study breeding system, pollinators, seed production, and seed dispersal (Knight 1993).

Ex Situ Needs
  Collect seeds periodically to maintain viable seeds in storage. Collect from all sub-populations.
Determine propagation and re-introduction protocols.


Books (Single Authors)

Scoggan, H.J. 1978. The Flora of Canada. National Museums of CA, Publications in Botany.

Books (Edited Volumes)

James C. Hickman, Editor. 1993 The Jepson manual: Higher plants of California. Berkeley: University of California Press. 1400p.

Electronic Sources

NNHP. (2001). Detailed Rare Plant and Lichen Lists. Nevada Natural Heritage Program. http://www.state.nv.us/nvnhp/selists.htm. Accessed: 2002.

Journal Articles

Archibald, J.K.; Wolf, P.G.; Tepedino, V.J. 2001. Genetic relationships and population structure of the endangered Steamboat buckwheat, Eriogonum ovalifolium var. williamsiae (Polygonaceae). American Journal of Botany. 88, 4: 608-615.

Crawford, J.A.; VanDyke, W; Meyers, S.M.; Haensley, T.F. 1986. Fall diet of blue grouse dendragapus-obscurus-pallidus in Oregon USA. Great Basin Naturalist. 46, 1: 123-27.

Day, T.A.; Wright, R.G. 1989. Positive Plant Spatial Association with Eriogonum ovalifolium in Primary Succession on Cinder Cones: Seed-Trapping Nurse Plants. Vegetatation. 80, 1: 37-45.

Dunne, J.A.; Harte, J; Taylor K.J. 2003. Subalpine meadow flowering phenology responses to climate change: Integrating experimental and gradient methods. Ecological Monographs. 73: 69-86.

James, M.L.; Zedler, J. 2000. Dynamics of wetland and upland subshrubs at the salt marsh-coastal sage scrub ecotone. American Midland Naturalist. 143, 2: 298-311.

Morefield, J. 1992. Nevada rare plant law protects an endangered buckwheat. Biodiversity Network News. 5, 3: 4.

Perez, C.J.; Waller, S.S.; Moser, L.W. 1998. Seedbank characteristics of a nebraska sandhills prairie. Journal of Range Management. 51, 1: 55-62.

Reveal, J.L. 1981. Erigonum-Sorededium new species of pulvinate wild buckwheat polygonaceae from Utah USA. Great Basin Naturalist. 41, 2: 229-31.

Reveal, J.L. 1981. Notes on endangered buckwheats (Eriogonum: Polygonaceae) with three newly described from the western United States. Brittonia. 33, 3: 441- 448.

Richardson, C.A.; Henderson, D.M. 1999. Classification and ordination of the alpine plant communities of Railroad Ridge, White Cloud Peaks, Idaho. Great Basin Naturalist. 59, 1: 63-78.

Riley, T.Z.; Davis, C.A.; Smith, R.A. 1993. Autumn and winter foods of the lesser prairie-chicken (Tympanuchus pallidicinctus) (Galliformes: Tetraonidae). Great Basin Naturalist. 53, 2: 186-89.

Triplehron, C.A. 1980. Distribution of Lobometopon-Ovale in Texas USA: a lost species rediscovered. Southwestern Entomologist. 5, 2: 90-92.

USFWS. 1985. Extension of Comment Period for Public Hearing Requests for Eriogonum ovalifolium var. williamsiae (Steamboat Buckwheat) and Cupressus abramsiana (Santa Cruz Cypress). Federal Register. 50, 211: 45443-45444.

USFWS. 1985. Proposed Endangered Status for Eriogonum ovalifolium var. williamsiae (Steamboat Buckwheat). Federal Register;. 50, 177: 37252-37254.

USFWS. 1985. Protection Recommended for Three Plants. Endangered Species Technical Bulletin. 10, 10: 1, 5-6.

USFWS. 1985. Reopening of Comment Period on Proposed Endangered Status for Eriogonum ovalifolium var. williamsiae (Steamboat Buckwheat). Federal Register. 50, 228: 48617.

USFWS. 1995. Recovery Updates. Endangered Species Technical Bulletin. 20, 2: 18.


BLM. 1983. Plan for Steamboat Hot Springs geyser basin interpretive area. Reno, Nevada: Bureau of Land Management. Washoe County Parks and Recreation Department.

Knight, T.A. 1993. Steamboat Buckwheat Management Plan, SB Geo Lease Site, Washoe County, Nevada. Unpublished report submitted to SB Geo, Inc. p.14+.

Nelson, L.S. 1991. Survey Results and Recommended Mitigation for the Steamboat Buckwheat Eriogonum ovalifolium var. williamsiae at Steamboat Springs, Nevada. Reno, Nevada: Survey conducted for JBR Consultants Group by Linda S. Nelson, Botanical Resource Consultant. p.6.

NNHP. 2001. Nevada Rare Plant Atlas: Index to Maps and Fact Sheets. Portland, Oregon and Reno, Nevada: Carson City: Nevada Natural Heritage Program, compiled for the U.S. Department of the Interior, Fish and Wildlife Service. Grant EP-3-12.

Soper, C. 1987. Nevada Preserve Design: Steamboat Hot Springs. Unpublished Report. The Nature Conservancy, Great Basin Field Office.

TNC. 1991. Conservation agreement for the Steamboat Buckwheat at the Steamboat Hot Springs lease area, Washoe County, Nevada. Unpublished document. Nevada Nature Conservancy, Las Vegas and Far West Capital, Salt Lake City, Utah.

USFWS. 1995. Steamboat buckwheat (Eriogonum ovalifolium var. williamsiae) Recovery Plan. Portland, Oregon: U.S. Fish and Wildlife Service. p.32 + appendices.

Williams, M.J. 1982. Status Report for Eriogonum ovalifolium Nutt. var. williamsiae Reveal. Reno, Nevada: Unpublished Report presented to the US Fish and Wildlife Service. p.30.


Gonella, Michael Paul. 1994. Characterization of Rare Plant Habitat for Restoration in the San Bernardino National Forest. [M.S. Thesis]: San Jose State University. 151p.

  This profile was updated on 3/4/2010
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