Cardamine maxima

Flora North America states that they are maintaining this as a distinct species based on molecular studies, but it has not been seen with mature fruit or seeds. It had been thought to be a hybrid of C. concatenata and C. diphylla. It can be seen in Cornell's Mundy Wildflower Garden in spring. Compare with C. concatenata & C. diphylla. Among the identifying characteristics are: three leaves vs. two in C. diphylla; deeply incised lateral leaflets (looks almost like 5 leaflets, not 3) vs. mostly unlobed lateral leaflets in C. diphylla; much wider leaflets than C. concatenata (which also has deeply incised lateral leaflets); root rhizomes that show definite teeth similar to C. diphylla yet have strong swelling & narrowing along the length vs. C. concatenata with minimal-to-no teeth and easily broken into oblong segments and C. diphylla with minimal constrictions on the rhizome.