Crack Willow - Salix fragilis
Hybrid White Willow, Brittle Willow,
Salix x rubens
Tree or large shrub to 25 m. Twigs tan, pubescent. Leaf blades 3–10 cm long, narrowly lanceolate with serrate margins, glabrous to sparsely hairy, glaucous below. Female catkins 2–8 cm long, emerging with the leaves on leafy branchlets 1–3 cm long; scales pale, long-hairy, deciduous. Capsules 3–5 mm long, glabrous; stipes 0.5–1 mm long; styles ca. 0.5 mm long (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX
The identity of our common, naturalized tree willow has been the source of taxonomic and nomenclatural confusion. Most, if not all of our specimens may be hybrids between Salix fragilis and Salix alba or Salix alba and Salix euxina. The name Salix x rubens is sometimes applied to these hybrids (Dorn 2010, Argus 2010).
Introduced to much of temperate North America; native to Eurasia and cultivated as an ornamental or for wildlife habitat (Lesica et al. 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX).
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)
The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus vagans
, Bombus bifarius
, Bombus fervidus
, Bombus frigidus
, Bombus huntii
, Bombus melanopygus
, Bombus ternarius
, Bombus terricola
, Bombus sitkensis
, Bombus occidentalis
, Bombus pensylvanicus
, Bombus bimaculatus
, Bombus griseocollis
, Bombus impatiens
, and Bombus suckleyi
(Plath 1934, Macior 1968, Heinrich 1976, Thorp et al. 1983, Colla and Dumesh 2010, Colla et al. 2011, Koch et al. 2012, Williams et al. 2014).
- 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.
- 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. 1968. Bombus (Hymenoptera, Apidae) queen foraging in relation to vernal pollination in Wisconsin. Ecology 49:20-25.
- Plath, O.E. 1934. Bumblebees and their ways. New York, NY: Macmillan Company. 201 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.
- Williams, P., R. Thorp, L. Richardson, and S. Colla. 2014. Bumble Bees of North America. Princeton, NJ: Princeton University Press. 208 p.
- Additional ReferencesLegend: View Online Publication
Do you know of a citation we're missing?
- Argus, G. 2010. Salix. In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 16+ vols. New York and Oxford. Vol. 7.
- Culver, D.R. 1994. Floristic analysis of the Centennial Region, Montana. M.Sc. Thesis. Montana State University, Bozeman. 199 pp.
- Dorn, R.D. 2010. The genus Salix in North America north of Mexico. 59 pp.
- Lesica, P., M.T. Lavin, and P.F. Stickney. 2022. Manual of Montana Vascular Plants, Second Edition. Fort Worth, TX: BRIT Press. viii + 779 p.
- Little, E.L., Jr. 1979. Checklist of United States trees (native and naturalized). Agriculture Handbook No. 541. U.S. Forest Service, Washington, D.C. 375 pp.