Nevada Fish & Wildlife Office
Pacific Southwest Region

Webber ivesia
(Ivesia webberi)
Class: Magnoliopsida
Order: Rosales
Family: Rosaceae
Genus: Ivesia
Species: webberi
Habitat: Shallow shrink-swell clay soils with a gravelly surface layer over volcanic, generally andesitic bedrock, on mid-elevation benches and flats at elevations of 1360-1820 m
 

Official Status:
Candidate
 

Life History:

A perennial, tap-rooted low spreading herb to 2.5 dm across, hairy throughout; overall color greenish-gray foliage with dark red stems and bright-yellow clusters of flowers, the whole plant becoming reddish-tinged late in the season. Leaves 3-7 cm long, mostly basal, with 4-8 pairs of leaflets crowded toward tips; leaflets 3-10 mm long, each further divided into 2-5 narrow segments. Flower clusters at stem tips, about 15-50 mm across, with 5-15 flowers each; each flower about 10 mm across on a stalk 1-8 mm long, petals 5, bright yellow, 2-3 mm long, much smaller than the green sepals; stamens 5.

 

Distribution and Habitat:

 

Found in Sierra, Dog and Honey Lake Valleys, Sierra and Lassen Counties, Western Nevada and adjacent eastern California. Known from Upper Long Valley on the California-Nevada border, and elsewhere in Nevada from both north and southwest of Reno, Washoe County, and from the western slope of the Pine Nut Mountains, Douglas County. When the disjunct Douglas County, Nevada, occurrence is excluded, range extent decreases from about 1600 km2 to under 1000 km2. California drew a least square around the known occurrences in 2005 and estimated range size there as 2800 sq mi.

Shallow shrink-swell clay soils with a gravelly surface layer over volcanic, generally andesitic bedrock, on mid-elevation benches and flats at elevations of 1360-1820 m, usually codominating with Artemisia arbuscula and Elymus elymoides in association with Antennaria dimorpha, Balsamorhiza hookeri, Erigeron bloomeri, Lewisia rediviva, Viola beckwithii, etc. Ivesia webberi has been found only in relatively open plant associations where competition for light and moisture with other species is low. It is absent from adjacent, otherwise appropriate habitat where deeper soils and taller, denser vegetation has developed.

 

Threats:
 

urban development, authorized and unauthorized roads, off-road vehicle activities and other dispersed recreation, livestock grazing and trampling, fire and fire suppression activities including fuels reduction and prescribed fires, and displacement by noxious weeds

 

Actions / Current Information:

 
Date Citation Title
11/09/2009 74 FR 57803 57878 Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Notice of Findings on Resubmitted Petitions; Annual Description of Progress on Listing Actions
12/10/2008 73 FR 75175 75244 Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Notice of Findings on Resubmitted Petitions; Annual Description of Progress on Listing Actions; Proposed Rule
12/06/2007 72 FR 69033 69106 Review of Native Species That Are Candidates for Listing as Endangered or Threatened; Annual Notice of Findings on Resubmitted Petitions; Annual Description of Progress on Listing Actions; Proposed Rule
09/12/2006 71 FR 53755 53835 Review of Native Species That Are Candidates or Proposed for Listing as Endangered or Threatened; Annual Notice of Findings on Resubmitted Petitions; Annual Description of Progress on Listing Actions
05/11/2005 70 FR 24869 24934
Endangered and Threatened Wildlife and Plants; Review of Native Species That Are Candidates or Proposed for Listing as Endangered or Threatened; Annual Notice of Findings on Resubmitted Petitions; Annual Description of Progress on Listing Actions; Proposed Rule
     
     
Last updated: September 28, 2012