Taxon Report

Allium howellii Eastw. var. sanbenitense (Traub) McNeal & T.D. Jacobsen

San Benito onion

Print Report

Taxon Summary

Allium howellii var. sanbenitense, commonly known as San Benito onion, is a perennial bulbiferous herb in the Alliaceae that is found only in California. It occurs within Chaparral (openings), and Valley and foothill grassland, growing at elevations from 390 to 1365 meters. Allium howellii var. sanbenitense is ranked 1B.3, Plants Rare, Threatened or Endangered in California and Elsewhere; Not very threatened in California.

Classification


Scientific Name:	Allium howellii Eastw. var. sanbenitense (Traub) McNeal & T.D. Jacobsen
Common Name:	San Benito onion
Family:	Alliaceae
Element Code:	PMLIL02163
USDA Plants Symbol:	ALHOS
Synonyms/Other Names:

Ecology and Life History


Lifeform:	perennial bulbiferous herb
Blooming Period: Apr-May	Apr-May
Elevation:	390-1365 (1280-4480)
General Habitats:	Chaparral, Valley and foothill grassland
Microhabitat:	Clay, Slopes (often)
Microhabitat Details:

Conservation Status


CA Rare Plant Rank:	1B.3
Global Rank:	G3G4T3
State Rank:	S3
State List:	None
Fed List:	None
Other Status:	BLM_S; SB_SBBG
CRPR Changes:	added to 1B.3 on 2017-04-04

Occurrence Data from the CNDDB


Total Occurrences:	18
Element Occurrence Ranks:
Excellent (A)	0
Good (B)	2
Fair (C)	0
Poor (D)	0
None (X)	0
Unknown (U)	16

Location


California Endemic: True
California Counties and Islands: Name (Code)
Fresno (FRE), Monterey (MNT), San Benito (SBT)
Quads: Name (Quad Code)
Ciervo Mtn. (3612045), Idria (3612046), Mercey Hot Springs (3612067), Panoche (3612057), Priest Valley (3612026), Tumey Hills (3612056)

Threat List Data from the CNDDB


Threat List Total:	2
EOs with Threat Listed:	Total EOs	% of EOs
	1	6 %
Grazing	1	5%
ORV activity	1	5%

Notes



Possibly threatened by grazing and development. See Herbertia 12:68 (1945) for original description, and Plant Life 28:66 (1972) and Flora of North America 26:251 (2003) for revised nomenclature.
Threats:

Taxonomy:

Selected References

Proposed Addition of A. howellii var. sanbenitense to CRPR 1B.3, G3G4T2 / S2 (2017)

Citation California Native Plant Society, Rare Plant Program. 2025. Rare Plant Inventory (online edition, v9.5.1). Website https://www.rareplants.cnps.org [accessed 25 October 2025].