Taxon Report

Allium yosemitense Eastw.

Yosemite onion

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Taxon Summary

Allium yosemitense, commonly known as Yosemite onion, is a perennial bulbiferous herb in the Alliaceae that is found only in California. It occurs within Broadleafed upland forest, Chaparral, Cismontane woodland, and Lower montane coniferous forest, growing at elevations from 535 to 2200 meters. Allium yosemitense is ranked 1B.3, Plants Rare, Threatened or Endangered in California and Elsewhere; Not very threatened in California.

Classification


Scientific Name:	Allium yosemitense Eastw.
Common Name:	Yosemite onion
Family:	Alliaceae
Element Code:	PMLIL022L0
USDA Plants Symbol:	ALYO
Synonyms/Other Names:

Ecology and Life History


Lifeform:	perennial bulbiferous herb
Blooming Period: Apr-Jul	Apr-Jul
Elevation:	535-2200 (1755-7220)
General Habitats:	Broadleafed upland forest, Chaparral, Cismontane woodland, Lower montane coniferous forest
Microhabitat:	Granitic (sometimes), Metamorphic (sometimes), Rocky
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.3
Global Rank:	G3
State Rank:	S3
State List:	CR
Fed List:	None
Other Status:	SB_UCSC; USFS_S
CRPR Changes:

Occurrence Data from the CNDDB


Total Occurrences:	14
Element Occurrence Ranks:
Excellent (A)	4
Good (B)	1
Fair (C)	0
Poor (D)	1
None (X)	0
Unknown (U)	8

Location


California Endemic: True
California Counties and Islands: Name (Code)
Mariposa (MPA), Tuolumne (TUO)
Quads: Name (Quad Code)
Ascension Mtn. (3711978), Buckingham Mtn. (3711957), El Capitan (3711966), El Portal (3711967), Wawona (3711956)

Threat List Data from the CNDDB


Threat List Total:	5
EOs with Threat Listed:	Total EOs	% of EOs
	4	29 %
Erosion/runoff	1	7%
Mining	1	7%
Other	1	7%
Recreational use (non-ORV)	1	7%
Road/trail construction/maint.	1	7%

Notes




Threats:
Possibly threatened by recreational activities.
Taxonomy:
See Leaflets of Western Botany 1:132-133 (1934) for original description, and Aliso 11(1):27-35 (1985) for taxonomic treatment.

Selected References

Fremontia 8(1):15-18 (1980) for information on rediscovery

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 12 November 2025].