Taxon Report

Sidalcea stipularis J.T. Howell & G. True

Scadden Flat checkerbloom

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Taxon Summary

Sidalcea stipularis, commonly known as Scadden Flat checkerbloom, is a perennial rhizomatous herb in the Malvaceae that is found only in California. It occurs within Marshes and swamps, growing at elevations from 700 to 730 meters. Sidalcea stipularis is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.

Classification


Scientific Name:	Sidalcea stipularis J.T. Howell & G. True
Common Name:	Scadden Flat checkerbloom
Family:	Malvaceae
Element Code:	PDMAL110R0
USDA Plants Symbol:	SIST3
Synonyms/Other Names:

Ecology and Life History


Lifeform:	perennial rhizomatous herb
Blooming Period: Jul-Aug	Jul-Aug
Elevation:	700-730 (2295-2395)
General Habitats:	Marshes and swamps
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.1
Global Rank:	G1
State Rank:	S1
State List:	CE
Fed List:	None
Other Status:	SB_CalBG/RSABG
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	2
Element Occurrence Ranks:
Excellent (A)	0
Good (B)	0
Fair (C)	1
Poor (D)	1
None (X)	0
Unknown (U)	0

Location


California Endemic: True
California Counties and Islands: Name (Code)
Nevada (NEV)
Quads: Name (Quad Code)
Chicago Park (3912028), Grass Valley (3912121)

Threat List Data from the CNDDB


Threat List Total:	6
EOs with Threat Listed:	Total EOs	% of EOs
	2	100 %
Altered flood/tidal/hydrologic regime	2	100%
Non-native plant impacts	2	100%
Other	2	100%
Road/trail construction/maint.	2	100%
Biocides	1	50%
Grazing	1	50%

Notes



Known from only two occurrences near Grass Valley. One occurrence voluntarily protected by landowner. Threatened by altered hydrology, grazing, mowing, and non-native plants. See Four Seasons 4(4):20-22 (1974) 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 10 February 2025].