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Montana Field Guide

Montana Field Guides

American Bird's-foot Trefoil - Lotus unifoliolatus
Other Names:  Lotus purshianus

Native Species

Global Rank: G5
State Rank: SNR

Agency Status


External Links

General Description
Taprooted annual. Stems often simple, erect, 5–30 cm. Herbage villous. Leaves nearly sessile, with 3 (1 or 5) narrowly elliptic leaflets, 5–20 mm long. Inflorescence of solitary pedicellate flowers subtended by a leaflet-like bract. Flowers pale yellow; calyx tube ca. 1 mm long; sepals linear, 2–5 mm long; keel 4–8 mm long. Legume 15–35 mm long (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Our plants are variety helleri (Britton) Isley.

Species Range

Range Comments
BC to MN, south to CA, TX, AL and Mexico (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Observations in Montana Natural Heritage Program Database
Number of Observations: 15

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



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

Sparsely vegetated soil of grasslands, woodlands, roadsides; plains, valleys(Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus vagans, Bombus fervidus, Bombus occidentalis, Bombus pensylvanicus, and Bombus griseocollis (Thorp et al. 1983, Colla and Dumesh 2010, Colla et al. 2011).

  • Literature Cited AboveLegend:   View Online Publication
    • Colla, S., L. Richardson, and P. Williams. 2011. Bumble bees of the eastern United States. Washington, DC: USDA Forest Service, Pollinator Partnership. 103 p.
    • 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.
    • Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
    • 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.
  • Additional ReferencesLegend:   View Online Publication
    Do you know of a citation we're missing?
    • DuBois, K.L. 1979. An inventory of the avifauna in the Long Pines of Southeastern Montana. M.Sc. Thesis. Bozeman, MT: Montana State University. 113 p.
  • Web Search Engines for Articles on "American Bird's-foot Trefoil"
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Citation for data on this website:
American Bird's-foot Trefoil — Lotus unifoliolatus.  Montana Field Guide.  .  Retrieved on , from