You were close. Thanks. I found it under 2 different names: Lactuca canadensis and Lactuca quercina.
EatTheWeeds.com calls it the former and PFAF.org, the latter. Both have the same description. They say leaves are edible raw or cooked before it flowers but it does come with some warnings. I took one bite of a leaf. It tasted a bit like kale. It did not make me sick, but that was just one bite.