A Case of Mistaken Identity

I've made a faux pas, a gaffe, a grave error! I've been a victim of my own horticultural hubris! I have (gasp) misidentified plants! No one accused me of this; I accuse myself.

Today during my walk in the Sachuest Point National Wildlife Refuge I finally figured out the difference between Spotted Knapweed and Canadian Thistle, and this in turn cleared the way for the proper identification of Bull Thistle. So to atone for my errors, here's the straight dope.

This is Spotted Knapweed, which I misidentified as Canadian Thistle a little while ago in talking about the plants in the meadow on the floor of the old quarry in Ballard Park.

This, on the other hand, is Canadian Thistle, which I misidentified in the same place as Bull Thistle.

And this, finally, is the real Bull Thistle. As you can see, we're not quite to the blooming stage yet. Maybe next week, but I'll be generous and say two weeks. 

Ironically, I got all this right last year in IDing the plants in pictures I posted to Wunderphotos. Why I forgot all that (or didn't think to look back before I opened my big yap this year) is beyond me. Job stress maybe? Yeah, we'll blame it on that.