Thistle of some kind.

Do not let it go to seed, and dig out as much of the root as you can. You don't want this in your garden.

Next time you want to try old seeds, you might want to do a germination test: put some in a ziploc baggie with a moistened paper towel. Viable seeds should sprout in a few days to a week.

Thank you very much for your assistance!

It is a thistle. I've been reading about them being edible....so, I think I'll harvest this one and try it. :) Will let you know what it tastes like.

that is a type if ''thistle'' and the post up there is right. it has seeds the will blow in the wind and go all over. its nasty little devil too. will leave a small thorn in you. im in florida and its ubiquitous here. the get tall and have a lavender flower. hope this helps you.

Well....I harvested the thistle today. BTW, it is a sow thistle.
The stalk (raw) tasted bitter, so I just harvested the leaves and discarded the stalk. Cooked the leaves for about 15 minutes in water until tender. Then buttered and salted them and ate them with dinner tonight. Very interesting taste and texture. The taste was a little like a mustard green (but not exact). The texture was VERY interesting. The spines were softened and easy to eat, but you could still feel them on your tongue. I've had no ill effect!! Yummy!!
So, I've harvested the seeds and planted them and will be enjoying more cooked thistles in the future.
Thank you for your feedback. Let me know what you think!

Oh....a side note. My husband thinks I'm nuts and was prepared to take me to the hospital. He told me later tonight, he is happy to have been wrong, but has no interest in trying any cooked thistle.