I suspect Canada thistle.

If so, dig them out rather than pull and break them off. If Canada thistle, you'll see they are connected by underground runners.

YIKES! I popped them out, sorta like dandelions. I did not see runners, but maybe that was deeper in the ground.

in these pictures they almost look like sow thistles. you'll be able to tell for yourself by the sharp spines. if it's a true thistle, those spines will always be sharp where as the sow thistle isnt that sharp to begin with, and they go limp shortly after picking it. If it's sow thistle, you've found yourself a fine salad green.

I'm fairly certain they stay sharp after I pull them. Last year I grabbed them a few days after pulling them and the spines went through my glove. Ouch!