Taxon Report

Sidalcea robusta Roush

Butte County checkerbloom

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Taxon Summary

Sidalcea robusta, commonly known as Butte County checkerbloom, is a perennial rhizomatous herb in the Malvaceae that is found only in California. It occurs within Chaparral, and Cismontane woodland, growing at elevations from 90 to 1600 meters. Sidalcea robusta is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.

Classification


Scientific Name:	Sidalcea robusta Roush
Common Name:	Butte County checkerbloom
Family:	Malvaceae
Element Code:	PDMAL110P0
USDA Plants Symbol:	SIRO2
Synonyms/Other Names:

Ecology and Life History


Lifeform:	perennial rhizomatous herb
Blooming Period: Apr-Jun	Apr-Jun
Elevation:	90-1600 (295-5250)
General Habitats:	Chaparral, Cismontane woodland
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.2
Global Rank:	G2
State Rank:	S2
State List:	None
Fed List:	None
Other Status:	BLM_S; SB_UCSC
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	38
Element Occurrence Ranks:
Excellent (A)	3
Good (B)	5
Fair (C)	1
Poor (D)	0
None (X)	1
Unknown (U)	28

Location


California Endemic: True
California Counties and Islands: Name (Code)
Butte (BUT)
Quads: Name (Quad Code)
Cherokee (3912165), Chico (3912167), Cohasset (3912186), Hamlin Canyon (3912166), Paradise West (3912176), Richardson Springs (3912177)

Threat List Data from the CNDDB


Threat List Total:	12
EOs with Threat Listed:	Total EOs	% of EOs
	9	24 %
Grazing	5	13%
Other	4	10%
Development	3	7%
ORV activity	2	5%
Erosion/runoff	1	2%
Foot traffic/trampling	1	2%
Agriculture	1	2%
Biocides	1	2%
Recreational use (non-ORV)	1	2%
Road/trail construction/maint.	1	2%
Improper burning regime	1	2%
Non-native plant impacts	1	2%

Notes



Threatened by non-native plants. Possibly threatened by residential development and fire suppression. See Annals of the Missouri Botanical Garden 18:205-207 (1931) for original description.
Threats:

Taxonomy:

Selected References

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 November 2025].