Taxon Report

Ivesia webberi Gray

Webber's ivesia

Print Report


© 2007 Steve Matson

Taxon Summary

Ivesia webberi, commonly known as Webber's ivesia, is a perennial herb in the Rosaceae that is found in California and elsewhere. It occurs within Great Basin scrub (volcanic ash), Lower montane coniferous forest, and Pinyon and juniper woodland, growing at elevations from 1000 to 2075 meters. Ivesia webberi is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.


Ecology and Life History

Lifeform: perennial herb
Blooming Period: May-Jul May-Jul
Elevation: 1000-2075 (3280-6810)
General Habitats: Great Basin scrub, Lower montane coniferous forest, Pinyon and juniper woodland
Microhabitat: Gravelly (sometimes), Sandy (sometimes)
Microhabitat Details:

Occurrence Data from the CNDDB

Total Occurrences: 13
Element Occurrence Ranks:
   Excellent (A) 2
   Good (B) 4
   Fair (C) 2
   Poor (D) 1
   None (X) 2
   Unknown (U) 2
California Endemic:  False
California Counties and Islands: Name (Code)
Lassen (LAS), Plumas (PLU), Sierra (SIE)
Quads: Name (Quad Code)
Chilcoot (3912072), Constantia (3912081), Crescent Mills (4012018), Dog Valley (3912051), Evans Canyon (3912061), Little Mud Flat (4012042), Meadow Valley (3912181), Quincy (3912088)*, Spring Garden (3912087), Taylorsville (4012017)

Threat List Data from the CNDDB

Threat List Total: 12
EOs with Threat Listed: Total EOs % of EOs
12 92 %
Non-native plant impacts 7 53%
ORV activity 7 53%
Grazing 7 53%
Improper burning regime 3 23%
Road/trail construction/maint. 3 23%
Other 3 23%
Development 3 23%
Foot traffic/trampling 2 15%
Agriculture 1 7%
Dam/Inundation 1 7%
Recreational use (non-ORV) 1 7%
Logging 1 7%

Notes

Known in CA only from Sierra and Dog valleys. Threatened by vehicles, and potentially by development, grazing, alteration of fire regimes, and non-native plants. Threatened in NV. See Proceedings of the American Academy of Arts and Sciences 10:71 (1874) for original description.
Threats:
Taxonomy:
Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 5 February 2025].