As far as I know, this is a wood-sorrel, aka Oxalis, perhaps an oxalis articulata in this case? I think I might have needed to wait for the flower to bloom to know for sure. If anyone can id them properly, let us know
Lawn owners usually hate them around here, as they only want to see grass in their lawns, which means I only pick them where I know herbicides/pesticides aren't used (and hope there isn't runoff from somewhere else)
You put the sorrel in a glass jar and top with the vinegar so everything is covered. Let everything sit for 4-6 weeks shaking occasionally. And the end strain out the solids from the vinegar which is what you keep. The vinegar should have all the vitamins, minerals and beneficial plant components from the sorrel. The vinegar is great on a salad, added to a dish or to make a shrub. I usually mix a few ounces with juice or sparkling water. Best soda replacement