Taxon Report

Asclepias nyctaginifolia Gray

Mojave milkweed

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Taxon Summary

Asclepias nyctaginifolia, commonly known as Mojave milkweed, is a perennial herb in the Apocynaceae that is found in California and elsewhere. It occurs within Mojavean desert scrub, and Pinyon and juniper woodland, growing at elevations from 875 to 1700 meters. Asclepias nyctaginifolia is ranked 2B.1, Plants Rare, Threatened, or Endangered in California, But More Common Elsewhere; Seriously threatened in California.

  Classification
Scientific Name:
 Asclepias nyctaginifolia Gray
Common Name:
 Mojave milkweed
Family: Apocynaceae
Element Code: PDASC02190
USDA Plants Symbol: ASNY
Synonyms/Other Names:

Ecology and Life History
Lifeform: perennial herb
Blooming Period: May-Jun May-Jun
Elevation: 875-1700 (2870-5580)
General Habitats: Mojavean desert scrub, Pinyon and juniper woodland
Microhabitat:
Microhabitat Details:

Conservation Status
CA Rare Plant Rank: 2B.1
Global Rank: G4?
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 2.3 to 2.1 on 2009-03-10

Occurrence Data from the CNDDB
Total Occurrences: 67
Element Occurrence Ranks:
   Excellent (A) 1
   Good (B) 6
   Fair (C) 12
   Poor (D) 14
   None (X) 0
   Unknown (U) 34

Location
California Endemic:  False
California Counties and Islands: Name (Code)
San Bernardino (SBD)
Quads: Name (Quad Code)
Cajon (3411734), Castle Peaks (3511532), Clark Mtn. (3511555), East of Grotto Hills (3511521), Grotto Hills (3511522), Hackberry Mountain (3511512), Hart Peak (3511531), Ivanpah Lake (3511554), Mescal Range (3511545), Pachalka Spring (3511556), Pinto Valley (3511523), Valley Wells (3511546)

Threat List Data from the CNDDB

Threat List Total: 10
EOs with Threat Listed: Total EOs % of EOs
47 70 %
Development 30 44%
Road/trail construction/maint. 14 20%
ORV activity 7 10%
Biocides 3 4%
Grazing 3 4%
Mining 3 4%
Non-native animal impacts 2 2%
Erosion/runoff 1 1%
Foot traffic/trampling 1 1%
Recreational use (non-ORV) 1 1%

Notes
Threatened by solar energy development, road widening, and road maintenance. See Proceedings of the American Academy of Arts and Sciences 12:69 (1876) for original description, and Annals of the Missouri Botanical Garden 41:155-156 (1954) for taxonomic treatment.
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 23 February 2025].