Hi. I found this growing on a wet rock right by a waterfall in northeastern Pennsylvania. Assumed it was a fern but sent it to a biology prof at a local university and he said he wasn't sure it was even a fern but was going to check the technical manuals and get back to me which, unfortunately, he didn't. Any help much appreciated.

Reminds me of Cardamine.
Might it be Cardamine pensylvanica?

Quote..."Grows in moist to wet soils of low areas. Low wet woods, spring branches and moist bluffs."

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