Canada Thistle Cirsium arvense (Linnaeus) ScopoliNon-native  -  Invasive    Synonyms: Carduus arvensis, Creeping Thistle.
Kingdom Plantae   >   Division Tracheophyta   >   Class Magnoliopsida   >   Order Asterales   >   Family Asteraceae   >   Genus Cirsium   

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Canada Thistle in Caroline Co., Maryland (6/5/2016). Photo by Wayne Longbottom. (MBP list)

Canada Thistle in Queen Anne's Co., Maryland (7/5/2016). Photo by Wayne Longbottom. (MBP list)

Canada Thistle in Howard Co., Maryland (5/22/2010). Photo by Bill Harms. (MBP list)

Canada Thistle blooming in Somerset Co., Maryland (6/2013). Photo by Lance Biechele. (MBP list)

Canada Thistle blooming in Calvert Co., Maryland (6/14/2014). Photo by John Hall. (MBP list)

Blooming Canada Thistle in Baltimore Co., Maryland (6/23/2013). Photo by Jim Brighton. (MBP list)

Canada Thistle blooming in Frederick Co., Maryland (6/25/2016). Photo by Richard Orr. (MBP list)

Canada Thistle in Montgomery Co., Maryland (9/22/2020). (c) Emily Summerbell, some rights reserved (CC BY-NC). Photo by Emily Summerbell, Ph.D. via iNaturalist. (MBP list)

Canada Thistle in Baltimore City, Maryland (6/14/2020). Photo by Kirsten Johnson. (MBP list)

Canada Thistle in Montgomery Co., Maryland (9/22/2020). (c) Emily Summerbell, some rights reserved (CC BY-NC). Photo by Emily Summerbell, Ph.D. via iNaturalist. (MBP list)

Canada Thistle blooming in Harford Co., Maryland (6/9/2018). Photo by Josh Emm. (MBP list)

Canada Thistle blooming in Allegany Co., Maryland (6/30/2013). Photo by Kimberly Booth. (MBP list)

The basal leaves of Canada Thistle in Kent Co., Maryland (4/3/2016). Photo by Nancy Martin. (MBP list)

Canada Thistle in Baltimore Co., Maryland (6/28/1981). Photo by Jim Stasz. (MBP list)

Canada Thistle in Baltimore City, Maryland (6/30/2020). (c) dangitmimi, some rights reserved (CC BY-NC). Photo by dangitmimi via iNaturalist. (MBP list)

Canada Thistle in Baltimore Co., Maryland (7/16/2020). (c) ebrown5813, some rights reserved (CC BY-NC). Photo by ebrown5813 via iNaturalist. (MBP list)

Canada Thistle in Kent Co., Maryland (7/10/2017). (c) dansmall, some rights reserved (CC BY-NC). Photo by Dan Small. (MBP list)

Canada Thistle in Montgomery Co., Maryland (8/10/2019). (c) Manoli Strecker, some rights reserved (CC BY-NC). Photo by Manoli Strecker via iNaturalist. (MBP list)

Canada Thistle in Dorchester Co., Maryland (9/8/2018). (c) Judy Gallagher, some rights reserved (CC BY). Photo by Judy Gallagher. (MBP list)

Canada Thistle in Frederick Co., Maryland (6/19/2019). (c) Steve Dudrow, some rights reserved (CC BY-NC). Photo by Steve Dudrow via iNaturalist. (MBP list)

Canada Thistle blooming in Carroll Co., Maryland (6/26/1994). Photo by Bob Ringler. (MBP list)

Canada Thistle in Baltimore City, Maryland (5/17/2019). (c) Brett M, some rights reserved (CC BY-NC). Photo by Brett M via iNaturalist. (MBP list)

Canada Thistle in Baltimore City, Maryland (5/17/2019). (c) Brett M, some rights reserved (CC BY-NC). Photo by Brett M via iNaturalist. (MBP list)

Canada Thistle in Washington Co., Maryland (9/25/2020). (c) smuller, some rights reserved (CC BY-NC). Photo by Sue Muller. (MBP list)

Canada Thistle in Montgomery Co., Maryland (11/7/2020). (c) bugzilla, some rights reserved (CC BY-NC). Photo by bugzilla via iNaturalist. (MBP list)

Canada Thistle in Montgomery Co., Maryland (11/7/2020). (c) bugzilla, some rights reserved (CC BY-NC). Photo by bugzilla via iNaturalist. (MBP list)

Canada Thistle in Baltimore Co., Maryland (5/25/2020). (c) Ashley M Bradford, some rights reserved (CC BY-NC). Photo by Ashley Bradford. (MBP list)


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MBP marks as "Invasive" any taxon listed in the Maryland Invasive Species Council (MISC) list of Invasive Species of Concern in Maryland. You can read their criteria and review the lists here: https://mdinvasives.org/species-of-concern/.

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