found in remnant channel/floodplain in a grazed pasture adjacent to Grove Creek in Greenville County.
while I am not 100 % certain, this looks suspiciously like the very invasive weed named Ficaria verna, the fig buttercup, which has started to establish in Greenville County and elsewhere. The state is trying to eradicate it wherever it is found. Please search the internet for SC sites on invasive species for more information and for confirmation. The mature leaves are usually not this toothed, but the growth habit as a ground cover and your description of the habitat looks dead on. This is a species that dies back before the weather gets really warm so it may not even be visible now. Another possibility is one of the wetland buttercups, Ranunculus, but I am afraid it is the Ficaria. If you have more pictures, especially as it appears now, please re-submit.
I apologize for the delay in my reply. I had software issues that only now have been fixed. Thank you for your patience.
Dr. Steven Hill, Botanist, SCNPS