Possibly worth bringing up this post again - I have two raised garden beds and intermix plants, with an eye not to put competetive plants or plant enemies close to each other. I find the plants are bigger, healthier and support each other, providing shaded soil and leaves, and planting closely provides weed suppression. Given that I'm in a hot dry climate, it makes sense. Plant further apart when you need to catch every ray. I find that I have fewer pests when I plant like nature and less like a clinical trial. It It's no good for commercial or large scale, but feeds hubby and I to repletion. Herbs, flowers and veg, all intermixed. When something goes or is harvested, I feed that area and put compost and/or manure there and plant in something else that would likely follow if I were doing rotation. Rows just give the caterpillars and slugs a good 'Roman Road' to follow, munching all the way! Intermixing brings all the predatory species that clear up the pests right into the area that they're wanted instead of being somewhat close-ish. It works for me in my area!

Not to further confuse, but Stylophorum is rather rare in that part of the Chicago region. Chelidonium majus looks very much a smaller version of Stylophorum diphyllum. While I can't tell which it is by the photo, you can separate them easily once they fruit shortly after flowering. Chelidonium majus has a long, smooth fruit with no style while Stylophorum diphyllum has a shorter, bristly fruit with a long style.

Probably covering it with the plastic delayed the decomposition, though unless leaves are ground up they can take some time to break down. That said, moving them aside and planting will probably work without a problem. It might take the soil a bit more time to warm up - though the black plastic should have taken care of that issue. Ruth Stout used to cover her entire veg garden with any organic matter she could get her hands on, and never tilled it - just added more mulch each year, pushed it aside to plant seed or seedlings, and pushed it back around the plants once they were up. (The Ruth Stout No-Work Garden Book) -Rosalinda

You do have a bit of Portulaca oleracea growing in the photo, just below the topmost plant in the center, the succulent looking, healthy green leaves. I think everything else is lambsquarters, Chenopodium album. They get a reddish-purplish bubbling looking leaf spot that I've read is caused by damage from a particular leaf-hopper, but I don't know that for sure having never witnessed the bug in action. If enough of the leaf is damaged, it gets the look yours has above. The bluish tone to the leaves was my clue, though I may be wrong. Chenopodium has this white sparkly coating on the young leaves that give it an overall bluish look.