Canada Thistle - Cirsium arvense
Creeping Thistle, California Thistle
Strongly rhizomatous perennial; individual stems unisexual. Stems erect, often branched above, 30–100 cm. Herbage glabrate; leaves sometimes tomentose beneath. Leaves short-petiolate, oblanceolate to elliptic, 3–15 cm long, dentate to deeply pinnate; lowest usually deciduous. Inflorescence few to several heads per stem in a corymbiform array; peduncles 0–4 cm long. Involucres 1–2 cm high; phyllaries imbricate in 6 to 8 series; the outer ovate with a darkened resinous keel-tip; inner linear; spines short or absent. Disk corollas purple; male 10–16 mm long, longer than the pappus; female 14–18 mm long, shorter than mature pappus. Achenes 2–4 mm long; collar absent (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)
Thistles of the genus Cirsium are distinguished by their plumose pappus from members of the genus Carduus which have minutely barbed, narrow ("capillary") bristles.
Despite its common name, Cirsium arvense is native to Eurasia and was apparently introduced to North America during the colonial period. By 1918, it was already on the noxious weed lists of 25 northern states. It is now widespread in all states and Canadian provinces north of 37 degrees N and south of 58-59 degrees N. Infestations are particularly troublesome in the northwest and northcentral states, and in the eastern provinces of Canada (Moore 1975).
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)
Moist, usually disturbed soil of fields, meadows, thickets, roadsides, woodlands, open forests, often along streams, wetlands; plains, valleys, montane (Lesica 2012. Manual of Montana Vascular Plants. BRIT Press. Fort Worth, TX)
- Additional ReferencesLegend: View Online Publication
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- Amor, R. L., and R. V. Harris. 1974. Distribution and seed production of Cirsium arvense (L.) Scop. in Vitoria, Australia. Weed Res. 14: 317-323.
- Bakker, D. 1960. A comparative life-history study of Cirsium arvense (L.) Scop. and Tussilago farfara (L.) the most troublesome weeds in the newly reclaimed polders of the former Zuiderzee. Pp. 205-222 in J. L. Harper, ed. The Biology of Weeds, Symp. British Ecology Socl., No. 1.
- Derschied, L. A., and R. E. Schultz. 1960. Achene development of Canada thistle and perennial sow thistle. Weeds 8: 55-62.
- Fernald, M.L. 1970. Gray's manual of botany. 8th ed. Van Nostrand Company, New York.
- Friesen, H. A. 1968. Trends in Canadian research to control Canada thistle. Proc. Northeast Weed Contr. Soc. 22: 27-36.
- Gleason, H. A. 1957. The New Britton and Brown Illustrated Flora of the Northeastern United States and Adjacent Canada. New York Botanical Garden, N. Y.
- Hamdoun, A. M. 1972. Regenerative capacity of root fragments of Cirsium arvense (L.) Scop. Weed Res. 12: 128-136.
- Hay, W. D. 1937. Canada thistle seed production and its occurrence in Montana seeds. Seed World. March 26, 1937.
- Hayden, A. 1934. Distribution and reproduction of Canada thistle in Iowa. Am. J. Bot. 21: 355-373.
- Hodgson, J. M. 1964. Variations in ecotypes of Canada thistle. Weeds 12: 167-171.
- Hope, A. 1927. The dissemination of weed seeds by irrigation water in Alberta. Sci. Agric. 7: 268-270.
- Hunter, J. H., and L. W. Smith. 1972. Environmental and herbicide effects on Canada thistle ecotypes (Cirsium arvense). Weed Sci. 20: 163-167.
- Kay, W. O. N. 1985. Hermaphrodites and subhermaphrodites in a reputedly dioecious plant, Cirsium arvense (L.) Scop. New Phytologist 100: 457-472.
- Lesica, P., M. T. Lavin, and P. F. Stickney. 2012. Manual of Montana Vascular Plants. Fort Worth, TX: BRIT Press. viii + 771 p.
- McAllister, R. S., and L. C. Haderlie. 1985. Effects of photoperiod and temperature on root bud development and assimilate translocation in Canada thistle (Cirsium arvense). Weed Science 33: 148-152.
- McIntyre, G. I., and J. H. Hunter. 1975. Some effects of nitrogen supply on growth and development of Cirsium arvense. Can. J. Bot. 53: 3012-3021.
- Moore, R. J., and C. Frankton. 1974. The thistles of Canada. Res. Bv. Canada Dept. Agric. Monograph No. 10, Ottawa, Canada.
- Roberts, H. A., and R. J. Chancellor. 1979. Periodicity of seedling emergence and achene survival in some species of Carduus, Cirsium, and Onopordum. J. Appl. Ecol. 16: 641-647.
- Sagar, G. R., and H. M. Rawson. 1964. The biology of Cirsium arvense (L.) Scop. Proc. British Weed Control Conf. 7: 553-562.
- Toole, E. H. 1946. Final results of the Duval buried seed experiment. Jour. of Agric. Res. 72:201-210.
- Van Bruggen, Theodore. 1976. The vascular plants of South Dakota. Iowa State Univ. Press, Ames. 538 pp.
- Wilson, R.G. 1979. Germination and seedling development of Canada thistle (Cirsium arvense). Weed Sci. 27: 146-151.