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Montana Field Guide

Montana Field Guides

Slender Trefoil - Lotus tenuis
Other Names:  Narrowleaf Trefoil

Non-native Species

Global Rank: GNR
State Rank: SNA
C-value: 1

Agency Status


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General Description
Taprooted perennial with a branched crown. Stems simple or branched, ascending to prostrate, 15–60 cm. Herbage glabrous to sparsely strigose. Leaves sessile, with 5 oblanceolate leaflets, 5–15 mm long. Inflorescence a long-pedunculate few-flowered umbel subtended by a trifoliolate bract. Flowers yellow, sometimes red-tinged; calyx tube 2–3 mm long with linear sepals 1–3 mm long; banner 6–10 mm long; keel 8–12 mm long. Legume 2–4 cm long (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Range Comments
Throughout much of North America; native to Eurasia (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).

Roadsides, fields, pastures; plains, valleys. Introduced for forage and to stabilize road banks (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.
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Citation for data on this website:
Slender Trefoil — Lotus tenuis.  Montana Field Guide.  .  Retrieved on , from