Taxon Report

Sidalcea calycosa Jones ssp. rhizomata (Jeps.) Munz

Point Reyes checkerbloom

Print Report

Taxon Summary

Sidalcea calycosa ssp. rhizomata, commonly known as Point Reyes checkerbloom, is a perennial rhizomatous herb in the Malvaceae that is found only in California. It occurs within Marshes and swamps (freshwater, and near coast), growing at elevations from 3 to 75 meters. Sidalcea calycosa ssp. rhizomata is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.

Classification


Scientific Name:	Sidalcea calycosa Jones ssp. rhizomata (Jeps.) Munz
Common Name:	Point Reyes checkerbloom
Family:	Malvaceae
Element Code:	PDMAL11012
USDA Plants Symbol:	SICAR
Synonyms/Other Names:

Ecology and Life History


Lifeform:	perennial rhizomatous herb
Blooming Period: Apr-Sep	Apr-Sep
Elevation:	3-75 (10-245)
General Habitats:	Marshes and swamps
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.2
Global Rank:	G5T2
State Rank:	S2
State List:	None
Fed List:	None
Other Status:
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	34
Element Occurrence Ranks:
Excellent (A)	1
Good (B)	17
Fair (C)	6
Poor (D)	1
None (X)	0
Unknown (U)	9

Location


California Endemic: True
California Counties and Islands: Name (Code)
Marin (MRN), Mendocino (MEN), Sonoma (SON)
Quads: Name (Quad Code)
Albion (3912327), Bolinas (3712286), Drakes Bay (3812218), Duncans Mills (3812341), Elk (3912326), Inverness (3812217), Petaluma (3812226), Petaluma River (3812225), San Rafael (3712285), Saunders Reef (3812376), Stewarts Point (3812364), Tomales (3812228), Valley Ford (3812238)

Threat List Data from the CNDDB


Threat List Total:	9
EOs with Threat Listed:	Total EOs	% of EOs
	20	59 %
Grazing	13	38%
Other	10	29%
Road/trail construction/maint.	6	17%
Foot traffic/trampling	5	14%
Non-native plant impacts	3	8%
Development	2	5%
Altered flood/tidal/hydrologic regime	1	2%
Mining	1	2%
Recreational use (non-ORV)	1	2%

Notes



Threatened by non-native plants, road maintenance, foot traffic, and pipeline construction. Possibly threatened by grazing. See Manual of the Flowering Plants of California, p. 629 (1925) by W.L. Jepson 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 3 April 2025].