I found this plant in a marshy part of my yard. It has white flowers, and thorns on the stems. I attached pics of the flowers and the leaves. Thanks!
Cool, thanks! I just read a little about it and it turns out that it's considered an invasive species. It's growing in a part of my yard that I can no longer mow because it is too wet almost continually. Now that I just let things grow back there, there's so many interesting things that pop up.