Taxon Report

Allium jepsonii (Traub) Denison & D. McNeal

Jepson's onion

Print Report


© 2019 Steven Perry

Species Description:
Allium jepsonii, commonly known as Jepson's onion, is a perennial bulbiferous herb in the Alliaceae that is found only in California. It occurs within Chaparral, Cismontane woodland, and Lower montane coniferous forest, growing at elevations from 300 to 1320 meters. Allium jepsonii is ranked 1B.2, Plants Rare, Threatened or Endangered in California and Elsewhere; Moderately threatened in California.

  Classification

Scientific Name:
Allium jepsonii (Traub) Denison & D. McNeal
Common Name:
Jepson's onion
Family: Alliaceae
Element Code: PMLIL022V0
USDA Plants Symbol: ALJE
Synonyms/Other Names:

Ecology and Life History

Lifeform: perennial bulbiferous herb
Blooming Period: Apr-Aug Apr-Aug
Elevation: 300-1320 (985-4330)
General Habitats: Chaparral, Cismontane woodland, Lower montane coniferous forest
Microhabitat: Serpentine, Volcanic
Microhabitat Details:

Occurrence Data from the CNDDB

Total Occurrences: 26
Element Occurrence Ranks:
   Excellent (A) 2
   Good (B) 14
   Fair (C) 3
   Poor (D) 0
   None (X) 0
   Unknown (U) 7
California Endemic:  True
California Counties and Islands: Name (Code)
Butte (BUT), El Dorado (ELD), Placer (PLA), Tuolumne (TUO)
Quads: Name (Quad Code)
Auburn (3812181), Berry Creek (3912164), Cherokee (3912165), Paradise East (3912175), Pulga (3912174), Shingle Springs (3812068), Sonora (3712084), Stirling City (3912185)

Threat List Data from the CNDDB

Threat List Total: 10
EOs with Threat Listed: Total EOs % of EOs
18 69 %
Road/trail construction/maint. 10 38%
Logging 9 34%
Other 3 11%
Recreational use (non-ORV) 2 7%
Non-native plant impacts 2 7%
Erosion/runoff 2 7%
Grazing 2 7%
Mining 1 3%
Development 1 3%
Vandalism/dumping/litter 1 3%

Notes

See Plant Life 28:63 (1972) for original description, and MadroƱo 36(2):122-130 (1989) for revised nomenclature.
Threats:
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 15 January 2025].