CPC Plant Profile: Webber Ivesia
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Plant Profile

Webber Ivesia (Ivesia webberi)

Flowers of Ivesia webberi Photo Credit: Carol Witham
  • Global Rank: G2 - Imperiled
  • Legal Status: Federally Threatened
  • Family: Rosaceae
  • State: CA, NV
  • Nature Serve ID: 151761
  • Date Inducted in National Collection: 12/01/2021

Ivesia webberi is a distinctive species that is not likely to be mistaken with other species. It is a perennial herb with greenish-gray foliage and dark red wiry stems. The flowers are yellow. Late in the season the whole plant becomes reddish-tinged. Its federal status is candidate. Until very recently, nearly all of its California occurrences and many of its Nevada occurrences were known only from historic herbarium collections (Witham 2000).

Participating Institutions
  • 09/01/2020
  • Orthodox Seed Banking

Based on an September 2020 extract of the California Plant Rescue Database, California Botanic Garden holds 1 accessions of Ivesia webberi in orthodox seed collection. There are as many as 10132 seeds of this species in their collection - although some may have been used for curation testing or sent to back up.

Nature Serve Biotics
  • 05/02/2017

Ivesia webberi is known from 14 extant occurrences scattered over a small portion of northeastern California and western Nevada. Many are vulnerable to encroaching residential development and attendant off-road vehicle and recreational use, and to livestock grazing. It occurs densely in some places,with more than 4,000,000 individual plants, but total occupied area is only about 200 acres.

Rita Dodge
  • 01/01/2010

Land development Road construction OHVs Livestock trampling Fire suppression activities Invasive species

Rita Dodge
  • 01/01/2010

There are 8 known populations in Nevada and 8 known populations in California. Unknown number if individuals

Rita Dodge
  • 01/01/2010

Current Knowledge and Conservation Status of Ivesia webberi Gray (Rosaceae), the Webber Ivesia, in Nevada. By, Witham 2000

Rita Dodge
  • 01/01/2010


Rita Dodge
  • 01/01/2010

Ex-situ seed conservation Propagation protocol development Habitat protection Reintroduction research Continued monitoring of current populations

Rita Dodge
  • 01/01/2010

Seed conservation Propagation protocol development Reintroduction research


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Taxon Ivesia webberi
Authority Gray
Family Rosaceae
CPC Number 6350
ITIS 25241
Common Names Webber's Ivesia | wire mousetail | Webber ivesia
Associated Scientific Names Ivesia webberi | Potentilla webberi | Horkelia webberi
Distribution Douglas and Washoe Counties of Nevada. Lassen, Plumas, and Sierra Counties of California.
State Rank
State State Rank
California S1
Nevada S1

Ivesia webberi is restricted to sites with sparse vegetation and shallow, clay soils derived from andesitic rock (Witham 2000). Occupied sites generally occur on mid-elevation flats, benches, or terraces on mountain slopes above and adjacent to large valleys. These sites tend to be wet in the spring but dry out as the season progresses. The high clay content in the soils creates a shrink-swell behavior as the soils wet and dry, which tends to heave rocks in the soil profile to the surface and creates a rocky surface pavement (Zamudio 1999).

Ecological Relationships


Common Name Name in Text Association Type Source InteractionID

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