Jode is absolutely correct.
Cinn. ferns are not good for you but ostrich ferns are. In Vermont, we find our ostrich ferns in the flood plains of the bigger rivers. My favorite way of eating them is to steam them, then cool them and toss them with a vinaigrette dressing. Pan fried with garlic and butter is hard to beat too.... I've pickled them as well, dill fiddle heads are quite tasty in December when greens are hard to come by....
Mike