You'll find them along wooded creeks and on riverbanks and in moist woodlands. "Fiddlehead" does not refer to a species of fern, but rather a stage in the plant's development, when the tender stalks have emerged but the fronds have yet to unfurl. That said, you don't want to eat just any fiddlehead, as some species of fern are carcinogenic. The most popular for eating (and the only one I trust) is the ostrich fern, which is bright green, often with a papery-brown covering on the head, and a deep, U-shaped stem. If your timing is perfect, you'll find them only a few inches tall and their tips tightly coiled, looking something like the heads—or scrolls—of so many miniature, bright-green fiddles (all buried up to their necks).