I remember Yellow Wood Sorrel (Oxalis stricta) as a plant mentioned in children’s books. I loved to read historical novels about girls growing up in America in the 18th or 19th century. These children walked in the woods with a parent or grandparent and learned the names of plants. I envied them for their ready access to the forest. Because I never learned the names of plants, I assumed that these and all the other flora mentioned had disappeared with “progress.”
I notice them mostly growing at the edge of sidewalks. My husband calls them “lemon flower” and occasionally ate them as a boy growing up in eastern Michigan. The shade of green is spectacular. I love its dull, flat finish.
Many homeowners in the neighborhood north of ours use lawn services that eliminate the clovers and the miniature blooms such as these. I’m always happy when I see yards that let their weeds and wildflowers grow freely. 
