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Montana Field Guide

Montana Field Guides

Fringed Onion - Allium fibrillum


Global Rank: G4
State Rank: S4
* (see State Rank Reason below)

Agency Status
USFWS:
USFS:
BLM:
MNPS Threat Rank:
C-value:

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State Rank Reason (see State Rank above)
See rank details.
  • Details on Status Ranking and Review
    Fringed Onion (Allium fibrillum) Conservation Status Review
    Review Date = 10/24/2012
    View State Conservation Rank Criteria
    Population Size

    Score0 - Large: Generally >100,000 individuals.

    Range Extent

    Score2 - Regional or State Endemic or Small Montana Range: Generally restricted to an area <100,000 sq. miles (equivalent to 2/3 the size of Montana or less) or Montana contributes 50% or more of the species’ range or populations OR limited to 2-3 Sub-basins in Montana.

    CommentRegional endemic.

    Area of Occupancy

    Score1 - Moderate: Generally occurring in 11-25 Subwatersheds (6th Code HUC’s).

    Environmental Specificity

    Score1 - Moderate: Species is restricted to a specific habitat that is more widely distributed or to several restricted habitats and is typically dependent upon relatively unaltered, good-quality habitat (C Values of 5-7).

    Trends

    Score0-1 - Stable to Minor Declines:

    CommentTrends unknown, though populations are likely stable or experiencing only minor declines.

    Threats

    Score1 - Medium: 11-30% of the populations are being negatively impacted or are likely to be impacted by one or more activities or agents, which are expected to result in decreased populations and/or habitat quality and/or quantity.

    CommentInvasive weeds may threaten some populations.

    Intrinsic Vulnerability

    Score0 - Low Vulnerability: Species does not have any unusual or specific life history or biological attributes or limted reproductive potential which makes it susceptible to extirpation from stochastic events or other adverse impacts to its habitat and thus slow to recover.

    Raw Conservation Status Score

    Score 5 to 6 total points scored out of a possible 19.

 
General Description
Bulbs globose to ovoid, usually solitary; outer coat membranous with obscure, contorted reticulations. Scapes terete, 3–15 cm. Leaves 2(–4), nearly flat, 1–3 mm wide, barely persistent. Umbel hemispheric with 10 to 20 flowers; pedicels 5–12 mm long; bracts 2, ovate, apiculate. Flowers white with green midveins; tepals 5–10 mm long; ovary with 3 low crests; stamens included. Seed surface smooth (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Phenology
Flowering June-early July.

Diagnostic Characteristics
The only other onion in northwest Montana that is usually less than 15 cm tall with only 2 leaves is A. textile, which has 3 bracts below the flower cluster and bulb coats that are very fibrous, resembling burlap.

Species Range
Present
 


Range Comments
Eastern OR and southeast WA, adjacent ID, and northwest MT. Regional endemic.

Summary of Observations Submitted for Montana
Number of Observations: 69

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density

Recency

 

(Observations spanning multiple months or years are excluded from time charts)



Habitat
Shallow, seasonally moist soils in the montane zone.

References
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Citation for data on this website:
Fringed Onion — Allium fibrillum.  Montana Field Guide.  .  Retrieved on , from