I found this on Garret Mountain in Paterson, New Jersey, USA. Does anybody know the name of this plant?
I think this is
Lysichiton americanus, skunk cabbage. It has these large, rolled-up leaves and grows in wet habitats as you describe. In Europe, it is an invasive species, but in America it is native. I am not 100% sure, because I don't know if there are any similar species in the US.
EDIT As Anongoodnurse pointed out, I was right to be unsure. This is Eastern skunk cabbage, Symplocarpus foetides. This species occurs in the Eastern parts of the USA.