Cirsium arvense (L.) Scop.
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Detail
- Family
- Asteraceae
- Botanical Name
- Cirsium arvense (L.) Scop.
- Common Name
- Canada Thistle, Field Thistle
- Synonym(s)
- Cirsium arvense (L.) Scop. var. arvense; Cirsium arvense (L.) Scop. var. horridum Wimmer & Graebner
- Flora of Virginia Name/Status
- Cirsium arvense (L.) Scop. var. arvense + Cirsium arvense (L.) Scop. var. horridum Wimmer & Graebner
- Comments
- A number of infraspecific segregates have been proposed based on pubescence, leaf division, and spininess. The very spiny var. horridum Wimmer & Graebner, in particular, is striking in its extreme expression, yet grades continuously into other, less spiny forms. FNA notes that "although extreme variants can be strikingly different, they are connected by such a web of intermediates that there seems to be little value in according any of them formal taxonomic recognition."
- Habitat
- A pernicious weed of various open, disturbed habitats that has spread rapidly in Virginia over the last several decades. It is frequent to common in the mountains and northern Piedmont, infrequent to rare (but spreading and possibly undercollected) elsewhere.
- Native Status
- Introduced
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