Taxon Report

Arabis rigidissima Rollins var. rigidissima

Trinity Mountains rockcress

Print Report


©2015 Dana York

Taxon Summary

Arabis rigidissima var. rigidissima, commonly known as Trinity Mountains rockcress, is a perennial herb in the Brassicaceae that is found only in California. It occurs within Upper montane coniferous forest (gravelly, and rocky), growing at elevations from 1190 to 2200 meters. Arabis rigidissima var. rigidissima is ranked 1B.3, Plants Rare, Threatened or Endangered in California and Elsewhere; Not very threatened in California.

  Classification
Scientific Name:
 Arabis rigidissima Rollins var. rigidissima
Common Name:
 Trinity Mountains rockcress
Family: Brassicaceae
Element Code: PDBRA061R2
USDA Plants Symbol: ARRIR
Synonyms/Other Names:

Ecology and Life History
Lifeform: perennial herb
Blooming Period: Jun-Aug Jun-Aug
Elevation: 1190-2200 (3905-7220)
General Habitats: Upper montane coniferous forest
Microhabitat:
Microhabitat Details:

Conservation Status
CA Rare Plant Rank: 1B.3
Global Rank: G3T2
State Rank:
 S2
State List: None
Fed List: None
Other Status:
CRPR Changes:
  • changed from 4.3 to 1B.3 on 2012-05-07

Occurrence Data from the CNDDB
Total Occurrences: 6
Element Occurrence Ranks:
   Excellent (A) 0
   Good (B) 1
   Fair (C) 0
   Poor (D) 0
   None (X) 0
   Unknown (U) 5

Location
California Endemic:  True
California Counties and Islands: Name (Code)
Siskiyou (SIS), Trinity (TRI)
Quads: Name (Quad Code)
Cecil Lake (4112312), Dees Peak (4112313), Eaton Peak (4112238), English Peak (4112342), Thurston Peaks (4012382), Whisky Bill Peak (4112215)

Threat List Data from the CNDDB

Threat List Total: 0
EOs with Threat Listed: Total EOs % of EOs
0 %

 

Notes
Similar to Boechera suffrutescens. See Boechera rigidissima in TJM 2; varieties not treated. See Rhodora 43(511):380-381 (1941) for original description, and Novon 13(4):381-391 (2003) for revised nomenclature.
Threats:
Taxonomy:
Similar to Boechera suffrutescens. See Boechera rigidissima in TJM 2; varieties not treated.

Selected References

Proposed Rank Change from CRPR 4.3, G3T3 / S3 to 1B.3, G3T2 / S2 (2012)
Arabis rigidissima var. rigidissima account for potential Species of Conservation Concern evaluation (2019)
Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 2 November 2025].