Taxon Report

Hymenoxys odorata DC.

bitter hymenoxys

Print Report


© 2015 Richard Spellenberg

Taxon Summary

Hymenoxys odorata, commonly known as bitter hymenoxys, is a annual herb in the Asteraceae that is found in California and elsewhere. It occurs within Riparian scrub, and Sonoran desert scrub, growing at elevations from 45 to 150 meters. Hymenoxys odorata is ranked 2B.1, Plants Rare, Threatened, or Endangered in California, But More Common Elsewhere; Seriously threatened in California.

  Classification
Scientific Name:
 Hymenoxys odorata DC.
Common Name:
 bitter hymenoxys
Family: Asteraceae
Element Code: PDAST530E0
USDA Plants Symbol: HYOD
Synonyms/Other Names:

Ecology and Life History
Lifeform: annual herb
Blooming Period: Feb-Nov Feb-Nov
Elevation: 45-150 (150-490)
General Habitats: Riparian scrub, Sonoran desert scrub
Microhabitat: Sandy
Microhabitat Details:

Conservation Status
CA Rare Plant Rank: 2B.1
Global Rank: G5
State Rank:
 S2
State List: None
Fed List: None
Other Status:
CRPR Changes:
  • changed from 2.1 to 2B.1 on 2013-06-12
  • changed from 2 to 2.1 on 2012-02-15
  • added to 2 on 2008-11-20

Occurrence Data from the CNDDB
Total Occurrences: 6
Element Occurrence Ranks:
   Excellent (A) 0
   Good (B) 0
   Fair (C) 0
   Poor (D) 0
   None (X) 0
   Unknown (U) 6

Location
California Endemic:  False
California Counties and Islands: Name (Code)
Imperial (IMP), Riverside (RIV), San Bernardino (SBD)
Quads: Name (Quad Code)
Blythe (3311455), Blythe NE (3311465), Cibola (3311436), Cross Roads (3411422), Gene Wash (3411432), McCoy Wash (3311466), Palo Verde (3311446), Ripley (3311456), Thumb Peak (3311447)

Threat List Data from the CNDDB

Threat List Total: 1
EOs with Threat Listed: Total EOs % of EOs
1 17 %
Development 1 16%

Notes
Most occurrences historical; need field surveys. Threatened by agriculture and development.
Threats:
Taxonomy:

Selected References

CRPR List Addition on 2008-11-20
Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 8 November 2025].