Ivesia webberi

Taxonomy 
Scientific Name:Ivesia webberi
Common name:Webber ivesia
Rank and Status   
Global Rank:G2 Native Status:Native
Subnational (State) Rank:S2 Endemic:No
US ESA Status:Listed threatened Sand Dunes:No
NNHP Tracking Status:At-Risk List Wetland:No
Other Agency Status Status Last Updated Status Comments
Bureau of Land Management - Nevada Sensitive BLM Nevada Sensitive Species List dated 2017-10-01
Bureau of Land Management - California Sensitive BLM California Special Status Plants List dated 2015-05-28
US Forest Service - Region 4 (Intermountain) Sensitive USFS list, Jan 2015 update
State of Nevada Protected Critically endangered
Nevada Native Plant Society Threatened
CCVI Score Presumed Stable
Distribution (NV Counties)

Status: Confident or certain

Douglas
Washoe
Summary Occurrence Data
Occurrence Count:10
Total Observed Area (hectares):12
Maximum Known Elevation (m):1806
Minimum Known Elevation (m):1219
Links
Ivesia webberi data at NatureServe
Ivesia webberi photos and data at Encyclopedia of Life
 
Character Abstract
Identification Comments:
Subspecies Comments:
Lookalikes:This distinctive species is not likely to be confused with other similar species. Most resembles I. unguiculata in the leaflets; but these are crowded on an inch or less of the rachis, and the villosity is less dense and silky; also the petals are smaller and bright yellow.
Phenology Comments:New leaves and flowering stems appear to emerge as soon as the soil temperatures are sufficiently high in the early spring. Populations in full flower have been observed during the last week of May, and some flowers have been seen opening throughout the month of June. Depending on annual timing of precipitation and temperature changes, flowering probably begins sometime between the beginning of May and early June and continues sporadically to the middle of July, especially on protected sites such as Dog Valley, CA. The fruit probably mature about a month after flowering, between mid-June and the end of July.
Reproduction Comments:No studies of reproduction or dispersal are known. Insect-mediated out-crossing is the most likely reproductive mode. Seed dispersal for this species is proably low to none. The seeds are relatively large and probably become lodged in crevices in the rocky pavement-like soils very soon after being shed by the parent plant. No asexual, or vegetative reproduction is apparent in this species.
Habitat Comments:Shallow shrink-swell clay soils with a gravelly surface layer over volcanic, generally andesitic bedrock, on mid-elevation benches and flats, usually codominating with Artemisia arbuscula and Elymus elymoides in association with Antennaria dimorpha, Balsamorhiza hookeri, Erigeron bloomeri, Lewisia rediviva, Viola beckwithii, etc.
Ecology Comments:No studies of the genetic structure are known. I. webberi grows in very close proximity with I. aperta var. canina and I. aperta var. aperta in Dog Valley, Sierra County, CA. No apparent hybridization occurs here and none is suspected to occur elsewhere. No evidence of disease, significant herbivory or other predation has been observed. At all sites, I. 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.
Inventory Comments:Surveys mostly complete.
Inventory Needs:
Version Date:
Images:
whole plant
Photographer: Carol Witham, for Nevada Natural Heritage Program
Photo Date:
close-up of flowers
Photographer: Carol Witham, for Nevada Natural Heritage Program
Photo Date:
close-up of flowers
Photographer: Carol Witham, for Nevada Natural Heritage Program
Photo Date:
close-up of leaf
Photographer: Carol Witham, for Nevada Natural Heritage Program
Photo Date:
late-season foliage
Photographer: Carol Witham, for Nevada Natural Heritage Program
Photo Date:
western habitat
Photographer: Carol Witham, for Nevada Natural Heritage Program
Photo Date:
eastern habitat
Photographer: Carol Witham, for Nevada Natural Heritage Program
Photo Date:
Ivesia webberi plant in flower
Photographer: Jim Morefield (Nevada Natural Heritage Program)
Photo Date: 26 April
Ivesia webberi flowering branches and leaves
Photographer: Jim Morefield (Nevada Natural Heritage Program)
Photo Date: 26 April
Ivesia webberi site and habitat Eagle Canyon Road Washoe County Nevada
Photographer: Jim Morefield (Nevada Natural Heritage Program)
Photo Date: 26 April
Ivesia webberi flowers
Photographer: Jim Morefield (Nevada Natural Heritage Program)
Photo Date: 26 April
Ivesia webberi fruiting stems and leaves
Photographer: Jim Morefield (Nevada Natural Heritage Program)
Photo Date: 19 May 2010
Ivesia webberi flowers and leaves against rock
Photographer: Jim Morefield (Nevada Natural Heritage Program)
Photo Date: 16 April
Ivesia webberi flowering plant
Photographer: Jim Morefield (Nevada Natural Heritage Program)
Photo Date: 16 April
Ivesia webberi flowers
Photographer: Jim Morefield (Nevada Natural Heritage Program)
Photo Date: 16 April