This toothwort, with larger flowers and wider leaves may qualify as large toothwort, Cardamine maxima. The toothworts at Riley Preserve varied from this wider leaf appearance to very narrow leaf divisions. The narrow were clearly Cardamine laciniata. Somewhere in the plentiful variation between those two was C. angustata. Whether those plants represent that species, or also include hybrids is a mystery to me. The shape of the tubers could have helped with identification, but I wasn't going to dig them up at this site. I never found one of these wide leaved plants with flowers that were good enough for a closeup.