which thistle is which?

9 years ago

I *thought* everything growing around here was Canada thistle (Cirsium arvense) but I'm not sure anymore. I'm pretty sure about the thistle that comes up in carpets...but then there's this other thistle that looks so similar but I just can't be sure. Its leaves are very sparsely spread up the stem and they seem (to my relatively untrained eye) to be narrower....but I do not know thistles well and I'm wondering if there isn't such great variation in appearance from one individual that both of these aren't C. arvense? Could someone please tell me if there are certain cues that one might look for that would give a definitive ID? I know that native thistles tend to be less thorny but again this is relative and it doesn't help me much. Thanks for ANY thistle input!

first pic is a Canada thistle to the left and ? to the right.

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Comments (4)

agkistrodon
Original Author
9 years ago
blurry pic of leaf but it gives the dimensions.
jekeesl (south-central Arkansas)
9 years ago
I can't see details well enough (more my eyes than your pics), but you might check Carduus crispus (Curly Plumeless Thistle) and Cirsium vulgare (Bull Thistle).
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agkistrodon
Original Author
9 years ago
Thanks so much jekeesl! I'm going to go w/ the C. crispus....bull is another name for scotch in the thistle world right? I know scotch thistle and it's not that...so I'll go w/ C. crispus...fitting name for a thistle!
jekeesl (south-central Arkansas)
9 years ago
Scotch Thistle is Onopordum acanthium. Bull Thistle is widely distributed across the US, and a different plant entirely. If you're interested, click on the link for the genus page at BONAP, and select one of the several thistle genera (such as Centaurea, Cirsium, Cnicus, Carduus, Cnicus, Salsola). You'll see the various species that have been recorded in your State/County to date.

Here is a link that might be useful: BONAP Maps