Robbins' Milkvetch - Astragalus robbinsii
Perennial from a loosely branched caudex. Herbage glabrate. Stems ascending to erect, 20–50 cm. Leaves with 7 to 17 lanceolate to oblanceolate leaflets, 10–25 mm long with rounded tips. Inflorescence longer than the leaves, secund with 7 to 12 spreading to declined flowers. Flowers pale purple; calyx black-strigose; sepals 1–2 mm long; banner reflexed, 9–10 mm long; keel 7–9 mm long. Legume pendent, linear-elliptic, triangular in cross section, 13–20 mm long, black- and white-strigose with a stipe 2–5 mm long (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX
Our plants are variety robbinsii
AK to NL south to WA, ID, CO, and VT (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
Astragalus robbinsii var. jesupii is known only from the shores of the Connecticut River in New Hampshire and Vermont. Three populations are known, two in New Hampshire, one in Vermont, all within a 16 mile stretch of the Connecticut River.
Observations in Montana Natural Heritage Program Database
Number of Observations:
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(Observations spanning multiple months or years are excluded from time charts)
Open forest, thickets, meadows, gravel bars, especially along rivers, streams; valleys, montane (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 appositus
, Bombus auricomus
, Bombus bifarius
, Bombus borealis
, Bombus centralis
, Bombus fervidus
, Bombus flavifrons
, Bombus huntii
, Bombus mixtus
, Bombus nevadensis
, Bombus rufocinctus
, Bombus ternarius
, Bombus terricola
, Bombus occidentalis
, Bombus pensylvanicus
, Bombus griseocollis
, and Bombus insularis
(Macior 1974, Thorp et al. 1983, Mayer et al. 2000, Colla and Dumesh 2010, Wilson et al. 2010, Koch et al. 2012, Miller-Struttmann and Galen 2014, Williams et al. 2014).
- 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.
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
- Macior, L.M. 1974. Pollination ecology of the Front Range of the Colorado Rocky Mountains. Melanderia 15: 1-59.
- Mayer, D.F., E.R. Miliczky, B.F. Finnigan, and C.A. Johnson. 2000. The bee fauna (Hymenoptera: Apoidea) of southeastern Washington. Journal of the Entomological Society of British Columbia 97: 25-31.
- 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. 208 p.
- Wilson, J.S., L.E. Wilson, L.D. Loftis, and T. Griswold. 2010. The montane bee fauna of north central Washington, USA, with floral associations. Western North American Naturalist 70(2): 198-207.