ID please - Prickly Lettuce, Lactuca serriola

...and it's growing in a lot of places, and I did not put it there.
Do you know what it is?

I can pull it up right by the base as there seem to be no thorns right where it comes out of the ground, and I get a lot of root quite easily when I pull.
I'm not sure how tall it might grow if I let it be.
Thanks for your ID help!

Likely it is Prickly Lettuce Lactuca serriola.

http://www.foragingtexas.com/2008/07/prickly-lettuce.html

I call it "wild lettuce". In my garden they grow 5 feet tall.

They are the same species as domesticated lettuce, and are fully cross-fertile with it, (albeit at a low rate cause lettuces are mostly-selfing). The wild lettuce is even more bitter than normal lettuce, so if I want to save lettuce seed, I make sure to do a good job weeding out the nearby wild lettuce.

Thanks!