Taxon Report

Hazardia detonsa (Greene) Greene

island hazardia

Print Report

Taxon Summary

Hazardia detonsa, commonly known as island hazardia, is a perennial evergreen shrub in the Asteraceae that is found only in California. It occurs within Chaparral, Closed-cone coniferous forest, and Coastal scrub, growing at elevations from 5 to 580 meters. Hazardia detonsa is ranked 4.3, Plants of Limited Distribution, A Watch List; Not very threatened in California.

Classification


Scientific Name:	Hazardia detonsa (Greene) Greene
Common Name:	island hazardia
Family:	Asteraceae
Element Code:	PDAST4H030
USDA Plants Symbol:	HADE4
Synonyms/Other Names:	Haplopappus detonsus

Ecology and Life History


Lifeform:	perennial evergreen shrub
Blooming Period: Mar-Nov	Mar-Nov
Elevation:	5-580 (15-1905)
General Habitats:	Chaparral, Closed-cone coniferous forest, Coastal scrub
Microhabitat:	Rocky, Volcanic
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	4.3
Global Rank:	G4
State Rank:	S4
State List:	None
Fed List:	None
Other Status:	SB_CalBG/RSABG
CRPR Changes:

Occurrence Data from the CNDDB


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

Location


California Endemic: True
California Counties and Islands: Name (Code)
Santa Barbara (SBA), Ventura (VEN)
Quads: Name (Quad Code)
Anacapa Island (3311983), Santa Cruz Island A (3311987), Santa Cruz Island B (3311986), Santa Cruz Island C (3311985), Santa Cruz Island D (3311984), Santa Rosa Island East (3311988), Santa Rosa Island North (3312081), Santa Rosa Island South (3312071), Santa Rosa Island West (3312082)

Threat List Data from the CNDDB


Threat List Total:	0
EOs with Threat Listed:	Total EOs	% of EOs
	0	0 %

Notes



Increasing on SCZ Isl. after reduction of feral sheep population. Hybridizes with H. squarrosa var. grindelioides. See Madroño 26(3):105-127 (1979) for revised nomenclature.
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 7 November 2025].