Taxon Report

Collomia larsenii (Gray) Payson

talus collomia

Print Report

Taxon Summary

Collomia larsenii, commonly known as talus collomia, is a perennial rhizomatous herb in the Polemoniaceae that is found in California and elsewhere. It occurs within Alpine boulder and rock field, Closed-cone coniferous forest, Subalpine coniferous forest, and Upper montane coniferous forest, growing at elevations from 2210 to 3500 meters. Collomia larsenii is ranked 2B.2, Plants Rare, Threatened, or Endangered in California, But More Common Elsewhere; Moderately threatened in California.

Classification


Scientific Name:	Collomia larsenii (Gray) Payson
Common Name:	talus collomia
Family:	Polemoniaceae
Element Code:	PDPLM02014
USDA Plants Symbol:	COLA8
Synonyms/Other Names:	Collomia debilis (Wats.) Greene var. larsenii (Gray) Brand

Ecology and Life History


Lifeform:	perennial rhizomatous herb
Blooming Period: Jul-Sep(Oct)	Jul-Sep(Oct)
Elevation:	2210-3500 (7250-11485)
General Habitats:	Alpine boulder and rock field, Closed-cone coniferous forest, Subalpine coniferous forest, Upper montane coniferous forest
Microhabitat:	Talus, Volcanic
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	2B.2
Global Rank:	G4
State Rank:	S2
State List:	None
Fed List:	None
Other Status:	USFS_S
CRPR Changes:	changed from 2.2 to 2B.2 on 2013-06-12

Occurrence Data from the CNDDB


Total Occurrences:	3
Element Occurrence Ranks:
Excellent (A)	1
Good (B)	1
Fair (C)	0
Poor (D)	0
None (X)	0
Unknown (U)	1

Location


California Endemic: False
California Counties and Islands: Name (Code)
Shasta (SHA), Siskiyou (SIS)
Quads: Name (Quad Code)
Lassen Peak (4012145), Little Glass Mtn. (4112156), Thousand Lakes Valley (4012165)

Threat List Data from the CNDDB


Threat List Total:	2
EOs with Threat Listed:	Total EOs	% of EOs
	2	67 %
Foot traffic/trampling	2	66%
Road/trail construction/maint.	1	33%

Notes



Known in CA from fewer than five occurrences. Threatened by foot traffic. On watch list in OR.
Threats:

Taxonomy:

Selected References

Collomia larsenii profile for potential Species of Conservation Concern evaluation (2021)

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 6 November 2025].