Fiddlehead Ferns = pohole = fiddlehead greens = fern. When a fern first emerges from the ground, its uncoiled frond is called a fiddlehead. Edible varieties of fiddleheads include those from the ostrich fern and the less common wood fern. . Fiddleheads from bracken ferns resemble those from ostrich ferns, but are believed to be carcinogenic. Be very careful if you're gathering fiddleheads from the wild. Undercooked ostrich fern fiddleheads also have been linked to some cases of food poison...