Taxon Report

Chorizanthe robusta Parry var. hartwegii (Benth.) Rev. & Morgan

Scotts Valley spineflower

Print Report

Taxon Summary

Chorizanthe robusta var. hartwegii, commonly known as Scotts Valley spineflower, is a annual herb in the Polygonaceae that is found only in California. It occurs within Meadows and seeps (sandy), Valley and foothill grassland (mudstone, and Purisima outcrops), growing at elevations from 230 to 245 meters. Chorizanthe robusta var. hartwegii is ranked 1B.1, Plants Rare, Threatened or Endangered in California and Elsewhere; Seriously threatened in California.

Classification


Scientific Name:	Chorizanthe robusta Parry var. hartwegii (Benth.) Rev. & Morgan
Common Name:	Scotts Valley spineflower
Family:	Polygonaceae
Element Code:	PDPGN040Q1
USDA Plants Symbol:	CHROH
Synonyms/Other Names:

Ecology and Life History


Lifeform:	annual herb
Blooming Period: Apr-Jul	Apr-Jul
Elevation:	230-245 (755-805)
General Habitats:	Meadows and seeps, Valley and foothill grassland
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.1
Global Rank:	G2T1
State Rank:	S1
State List:	None
Fed List:	FE
Other Status:	SB_UCSC
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	4
Element Occurrence Ranks:
Excellent (A)	0
Good (B)	3
Fair (C)	0
Poor (D)	0
None (X)	0
Unknown (U)	1

Location


California Endemic: True
California Counties and Islands: Name (Code)
Santa Cruz (SCR)
Quads: Name (Quad Code)
Felton (3712211), Laurel (3712118)

Threat List Data from the CNDDB


Threat List Total:	4
EOs with Threat Listed:	Total EOs	% of EOs
	3	75 %
Development	3	75%
Non-native plant impacts	3	75%
Other	3	75%
Road/trail construction/maint.	1	25%

Notes



Known only from Scotts Valley. Threatened by development, vehicles, and non-native plants. See C. robusta in TJM (1993). See Phytologia 67(5):357-360 (1989) for revised nomenclature, and Fremontia 24(4):8-11 (1996) for taxonomic discussion.
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 1 November 2025].