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Montana Field Guide

Montana Field Guides

Tapertip Onion - Allium acuminatum

Species of Concern
Native Species

Global Rank: G5
State Rank: S2S3
(see State Rank Reason below)

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

External Links






State Rank Reason (see State Rank above)
Rare in Montana, where it is known from several widely scattered sites in the western half of the state. Trend data are lacking. Threats to populations do not appear to be significant at this time, though invasive weeds may eventually pose problems at some sites.
 
General Description
Bulbs sometimes clustered, globose; outer coat dingy white, membranous, honeycombed. Scapes terete, 20–35 cm. Leaves 2 to 3, subterete to channeled, 0.5–2 mm wide, withering. Umbel hemispheric with 10 to 30 flowers; pedicels 5–25 mm long; bracts 2, lanceolate to ovate, acuminate. Flowers pink to magenta; outer tepals 7–14 mm long; inner tepals smaller; ovary obscurely crested; stamens included. Seed surface minutely roughened (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Phenology
Flowering May-June.

Diagnostic Characteristics
Allium acuminatum can be distinguished from most other species by having the combination of rose-colored outer tepals that are longer than the inner tepals, and more than 2 concave leaves. The more common A. brevistylum also has rose-colored tepals, but its leaves are usually more than 4 mm wide.

Species Range
Montana Range

Year-round
 


Range Comments
BC, MT south to CA, AZ and NM. Known from Ravalli and Sanders counties (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 47

(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
Dry, open forests and grasslands in the montane zone.
Predicted Suitable Habitat Model

This species has a Predicted Suitable Habitat Model available.

To learn how these Models were created see http://mtnhp.org/models

Ecology
POLLINATORS
The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus bifarius, Bombus centralis, Bombus flavifrons, Bombus huntii, Bombus melanopygus, Bombus sylvicola, Bombus occidentalis, and Bombus bohemicus (Macior 1974, Thorp et al. 1983, Colla and Dumesh 2010, Koch et al. 2012, Miller-Struttmann and Galen 2014, Williams et al. 2014).

References
  • Literature Cited AboveLegend:   View Online Publication
    • Colla, S.R. and S. Dumesh. 2010. The bumble bees of southern Ontario: notes on natural history and distribution. Journal of the Entomological Society of Ontario 141: 39-68.
    • Koch, J., J. Strange, and P. Williams. 2012. Bumble bees of the western United States. Washington, DC: USDA Forest Service, Pollinator Partnership. 143 p.
    • Macior, L.M. 1974. Pollination ecology of the Front Range of the Colorado Rocky Mountains. Melanderia 15: 1-59.
    • Miller-Struttmann, N.E. and C. Galen. 2014. High-altitude multi-taskers: bumble bee food plant use broadens along an altitudinal productivity gradient. Oecologia 176:1033-1045.
    • Thorp, R.W., D.S. Horning, and L.L. Dunning. 1983. Bumble bees and cuckoo bumble bees of California (Hymenoptera: Apidae). Bulletin of the California Insect Survey 23:1-79.
    • Williams, P., R. Thorp, L. Richardson, and S. Colla. 2014. Bumble Bees of North America. Princeton, NJ. Princeton University Press.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
    • Quire, R.L. 2013. The sagebrush steppe of Montana and southeastern Idaho shows evidence of high native plant diversity, stability, and resistance to the detrimental effects of nonnative plant species. M.Sc. Thesis. Bozeman, MT: Montana State University. 124 p.
    • Simanonok, M. 2018. Plant-pollinator network assembly after wildfire. Ph.D. Dissertation. Bozeman, MT: Montana State University. 123 p.
  • Web Search Engines for Articles on "Tapertip Onion"
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Citation for data on this website:
Tapertip Onion — Allium acuminatum.  Montana Field Guide.  .  Retrieved on , from