Taxon Report

Camissoniopsis hardhamiae (P.H. Raven) W.L. Wagner & Hoch

Hardham's evening-primrose

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Taxon Summary

Camissoniopsis hardhamiae, commonly known as Hardham's evening-primrose, is a annual herb in the Onagraceae that is found only in California. It occurs within Chaparral, and Cismontane woodland, growing at elevations from 140 to 945 meters. Camissoniopsis hardhamiae is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.


  Classification

Scientific Name:
Camissoniopsis hardhamiae (P.H. Raven) W.L. Wagner & Hoch
Common Name:
Hardham's evening-primrose
Family: Onagraceae
Element Code: PDONA030N0
USDA Plants Symbol:
Synonyms/Other Names:
  • Camissonia hardhamiae

Ecology and Life History

Lifeform: annual herb
Blooming Period: Mar-May Mar-May
Elevation: 140-945 (460-3100)
General Habitats: Chaparral, Cismontane woodland
Microhabitat: Burned areas (sometimes), Carbonate, Disturbed areas (sometimes), Sandy
Microhabitat Details:

Occurrence Data from the CNDDB

Total Occurrences: 22
Element Occurrence Ranks:
   Excellent (A) 6
   Good (B) 5
   Fair (C) 0
   Poor (D) 1
   None (X) 0
   Unknown (U) 10
California Endemic:  True
California Counties and Islands: Name (Code)
Monterey (MNT), San Luis Obispo (SLO)
Quads: Name (Quad Code)
Bear Canyon (3612113), Bradley (3512077), Camatta Ranch (3512043), Cosio Knob (3612112), Hames Valley (3512088), Morro Bay South (3512037), Pebblestone Shut-in (3512161), San Miguel (3512076), Santa Margarita (3512045), Santa Margarita Lake (3512034), Slack Canyon (3612016), Valleton (3512086), Wilson Corner (3512044)

Threat List Data from the CNDDB

Threat List Total: 12
EOs with Threat Listed: Total EOs % of EOs
11 50 %
Other 8 36%
Road/trail construction/maint. 6 27%
Grazing 4 18%
Foot traffic/trampling 3 13%
Military operations 3 13%
Feral pigs 2 9%
Biocides 1 4%
Erosion/runoff 1 4%
Mining 1 4%
Non-native plant impacts 1 4%
ORV activity 1 4%
Improper burning regime 1 4%

Notes

Threatened by proposed road construction in SLO Co; also threatened by grazing, mining, military activities, non-native plants, road maintenance, and vehicles. See Contributions from the U.S. National Herbarium 37(5):301 (1969) for original description.
Threats:
Threatened by proposed road construction in SLO Co; also threatened by grazing, mining, military activities, non-native plants, road maintenance, and vehicles.
Taxonomy:
Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 5 February 2025].