Spiny-leaf Sowthistle - Sonchus asper
Rough Milk Thistle, Sharp-fringed Sow Thistle, Prickly Sow Thistle, Spiny Sowthistle
Taprooted annual. Stems erect, 25–90 cm tall, simple or branched. Leaves oblong to oblanceolate, pinnately toothed or lobed less than halfway to the midvein, 5–20 cm long, winged-petiolate below, auriculate-clasping above. Involucres 8–14 mm high; phyllaries glabrous. Ray ligules 3–5 mm long, inconspicuous. Achenes tan to red-brown, 2–3 mm long, smooth between the ribs (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)
Introduced from Eurasia; in nearly all of North America except the Canadian high arctic.
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)
Disturbed soil of roadsides, pastures, lawns, streambanks; plains, valleys (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)
The following animal species have been reported as pollinators of this species or genera where their geographic ranges overlap: Bombus vagans
, Bombus bifarius
, Bombus fervidus
, and Bombus terricola
(Thorp et al. 1983, Colla and Dumesh 2010).
- 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.
- 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
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- Jones, W. W. 1901. Preliminary flora of Gallatin County. M.S. Thesis. Bozeman, MT: Montana State College. 78 pp.
- 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.
- Tuinstra, K. E. 1967. Vegetation of the floodplains and first terraces of Rock Creek near Red Lodge, Montana. Ph.D dissertation. Montana State University, Bozeman 110 pp.
- Zapatka, T.P. 1963. Some results of two limited hunting seasons on hen Pheasants in north central Montana. M.Sc. Thesis. Bozeman, Montana: Montana State University. 26 p.