I have yellow flowering plants covering the understory of our woodlands and I kept thinking it was marsh marigold, but it may be lesser celandine. I am attaching a picture. If that is what it is, what can we do? It is spreading everywhere.
The plant in your photo looks like lesser celandine, a non-native invasive plant. It spreads by tuberous roots and is difficult to control. See the publication from the Plant Conservation Alliance's Alien Plant Working Group for management options for lesser celandine