Euphorbia, though I don't recognize the species.

Here that would be E amygdaloides of which there are various cultivars as well as the native species. Don't know if E amygdaloides var. robbiae is grown in the US.

Here is a link that might be useful: E amygdaloides var. robiae

That may be our native E. commutata (Wood Spurge), which is common from western Arkansas to the east coast.

Thank you all. I brought a photo to the Master Gardener clinic and it is, indeed, Euphorbia, aka Wood Spurge.

It's Miner's Lettuce

Here is a link that might be useful: Native to the US and edible

It isn't Miners Lettuce. It's very clearly a Euphorbia. Look at the flowers again - they are quite different. Not mention the leaves. Euphorbias have milky white sap which can be irritant, so eating this would not be a good idea. If you are into foraging you need to be really clear on ids.