Taxon Report

Xanthisma gracile (Nuttall) D.R. Morgan & R.L. Hartman

annual bristleweed

Print Report

Taxon Summary

Xanthisma gracile, commonly known as annual bristleweed, is a annual herb in the Asteraceae that is found in California and elsewhere. It occurs within Joshua tree "woodland", and Mojavean desert scrub, growing at elevations from 1220 to 1555 meters. Xanthisma gracile is ranked 4.3, Plants of Limited Distribution, A Watch List; Not very threatened in California.

Classification


Scientific Name:	Xanthisma gracile (Nuttall) D.R. Morgan & R.L. Hartman
Common Name:	annual bristleweed
Family:	Asteraceae
Element Code:	PDAST640E0
USDA Plants Symbol:
Synonyms/Other Names:	Machaeranthera gracilis (Nutt.) Shinners

Ecology and Life History


Lifeform:	annual herb
Blooming Period: Apr-Jul(Sep)	Apr-Jul(Sep)
Elevation:	1220-1555 (4005-5100)
General Habitats:	Joshua tree "woodland", Mojavean desert scrub
Microhabitat:
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	4.3
Global Rank:	G5
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: False
California Counties and Islands: Name (Code)
San Bernardino (SBD)
Quads: Name (Quad Code)
Castle Peaks (3511532), Hart Peak (3511531), Havasu Lake (3411444), Pinto Valley (3511523)

Threat List Data from the CNDDB


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

Notes



See Phytologia 68(6):457 (1990) for taxonomic treatment and SIDA 20(4): 1405-1406 (2003) 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 31 October 2025].