CPC Plant Profile: Steamboat Buckwheat
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Plant Profile

Steamboat Buckwheat (Eriogonum ovalifolium var. williamsiae)

A closeup of the pink umbels (flowers) of this plant. Photo Credit: James D. Morefield
Description
  • Global Rank: N/A
  • Legal Status: N/A
  • Family: Polygonaceae
  • State: NV
  • Nature Serve ID: 133780
  • Date Inducted in National Collection: 02/09/1992

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.

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Updates
  • 09/10/2020
  • Propagation Research

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).

  • 09/10/2020
  • Genetic Research

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).

  • 09/10/2020
  • Seed Collection

Seeds stored at The Berry Botanic Garden.

  • 09/10/2020
  • Orthodox Seed Banking

Seeds stored at The Berry Botanic Garden.

Nature Serve Biotics
  • 05/02/2017

The species is entirely restricted to a 127-150 acre area near a single hot spring system in Washoe County, Nevada. It is abundant where it occurs, with tens of thousands of individual rosettes scattered throughout the area, but the habitat is very susceptible to degradation. The primary threat to the taxon is private development - a geothermal power plant has already been constructed and has impacted a part of the population, but the power company has developed a management plan to minimize the threat and has been proactive in the protection of the
buckwheat habitat. The remaining (and largest) part of the population, however, is potentially protectable but faces continued threats due to its location in an intensely developed area along a major highway. Development would quickly destroy the plants. In addition, illegal off-road vehicle use and refuse dumping have occurred; these activities may alter moisture patterns, a habitat parameter to which this taxon is especially sensitive. The plants appear to have low reproductive potential and any significant loss of individuals may severely affect the taxon's survival.

Edward Guerrant, Ph.D.
  • 01/01/2010

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 (Will

Edward Guerrant, Ph.D.
  • 01/01/2010

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).

Edward Guerrant, Ph.D.
  • 01/01/2010

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).

Edward Guerrant, Ph.D.
  • 01/01/2010

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.

Edward Guerrant, Ph.D.
  • 01/01/2010

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).

Edward Guerrant, Ph.D.
  • 01/01/2010

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

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Photos
Nomenclature
Taxon Eriogonum ovalifolium var. williamsiae
Authority Reveal
Family Polygonaceae
CPC Number 1769
ITIS 195562
USDA EROVW
Common Names steamboat buckwheat | wild buckwheat | William's buckwheat
Associated Scientific Names Eriogonum ovalifolium var. williamsiae
Distribution Localized near a hot springs in western Nevada.
State Rank
State State Rank
Nevada S1
Habitat

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)

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).

Pollinators
Common Name Name in Text Association Type Source InteractionID
Bees
Bees Floral Visitor Link
Butterflies & Moths
Butterflies Floral Visitor Link
Flies
Flies Floral Visitor Link
Other
Wasps Floral Visitor Link
Reintroduction
Lead Institution State Reintroduction Type Year of First Outplanting

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