Munz's Onion / Center For Plant Conservation
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Plant Profile

Munz's Onion (Allium munzii)

Photo Credit: Rancho Santa Ana
  • Global Rank: G1 - Critically Imperiled
  • Legal Status: Federally Endangered
  • Family: Liliaceae
  • State: CA
  • Nature Serve ID: 144778
  • Lifeform: Forb/herb
  • Date Inducted in National Collection: 03/08/1989

This elusive wetland perennial is hard to find. Despite producing 10 to 36 white flowers at a time, it only flowers during years with adequate rainfall, an event which doesn't always happen in Southern California. In fact, this species doesn't even produce leaves during the worst drought years, biding its time until it receives enough rain to grow. This makes it a very difficult plant to study, which is evident from the lack of information on the species. Censusing this plant can only properly be done during good growing years which makes conserving this plant a real challenge. However, this plant, like many wetland species, is at high risk of extinction. Wetlands are quickly disappearing from the American landscape along with those species endemic to them.

Where is Munz's Onion (Allium munzii) located in the wild?


Occurs in vernal pools and other wetlands, or on clay soils and moist grasslands generally on shallow slopes and is associated with Alo, Altamont, Bosanko, or Auld soils (USFWS 1998) This species is typically found in association with southern needle grass grassland, mixed grassland, and grassy openings in coastal sage scrub. It is only occasionally found in cismontane juniper woodlands with at least one specimen found associated with Stipa pulchra, Avena barbata, with a few Juniperus californica. (USFWS 1998)


Mesic clay soils in western Riverside County, California (USFWS 1998)

States & Provinces:

Munz's Onion can be found in California

Which CPC Partners conserve Munz's Onion (Allium munzii)?

CPC's Plant Sponsorship Program provides long term stewardship of rare plants in our National Collection. We are so grateful for all our donors who have made the Plant Sponsorship Program so successful. We are in the process of acknowledging all our wonderful plant sponsorship donors on our website. This is a work in progress and will be updated regularly.

Conservation Actions

  • 09/01/2020
  • Orthodox Seed Banking

Based on an September 2020 extract of the California Plant Rescue Database, California Botanic Garden holds 10 accessions of Allium munzii in orthodox seed collection. There are as many as 10113 seeds of this species in their collection - although some may have been used for curation testing or sent to back up.

  • 08/05/2020
  • Seed Collection

Based on an August 2020 extract of the California Plant Rescue Database, California Botanic Garden has collected 9 seed accessions of Allium munzii from 7 plant occurrences listed in the California Natural Diversity Database. These collections together emcompass 233 maternal plants

Nature Serve Biotics
  • 05/02/2017

Allium munzii is narrowly endemic to western Riverside County in southern California. Munz's onion is known from fifteen extant populations. It is extremely threatened by rapid and extensive urbanization, dry land farming activities, competition from non-native plants throughout its entire range, and off-road vehicle activities throughout a significant portion of its range. Other threats include, clay mining and grazing (CNPS 2001).

  • 01/01/2010

Development (both urban and agricultural) Clay mining Dryland farming activities Non-native grasses Off-road vehicles Fire suppression actions (i.e.. bulldozing and disking) Grazing by cattle and sheep (USFWS 1998)

  • 01/01/2010

13 populations in Western Riverside County CA, including the Gavilan Hills, Harford Springs County Park, Paloma Valley, Skunk Hollow, Domenigoni Hills, Bachelor Mountain and the Elsinore Mountains. It is estimated that the total number of plants is somewhere between 20,000 to 70,000 individuals. (USFWS 1998)

  • 01/01/2010

None known.

  • 01/01/2010

A few of the known populations occur on land managed by the Reserve Management Committees for the Riverside County multispecies plans, but a number of others occur on private lands with no management. One population occurs on Federal land. (USFWS 1998)

  • 01/01/2010

Basic biology An inventory of all populations Surveys of potential habitat

  • 01/01/2010

Maintain genetically representative seed bank.


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Taxon Allium munzii
Authority (Ownbey & Aase) McNeal
Family Liliaceae
CPC Number 75
ITIS 506825
Duration Perennial
Common Names Munz's onion
Associated Scientific Names Allium munzii | Allium fimbriatum var. munzii
Distribution Mesic clay soils in western Riverside County, California (USFWS 1998)
State Rank
State State Rank
California S1
Ecological Relationships

Common Name Name in Text Association Type Source InteractionID
Flower beetles Anthicidae Floral Visitor Link
March flies Bibio Floral Visitor Link

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