Noun | 1. | ![]() fiddlehead, Matteuccia struthiopteris, Onoclea struthiopteris, ostrich fern, Pteretis struthiopteris fern - any of numerous flowerless and seedless vascular plants having true roots from a rhizome and fronds that uncurl upward; reproduce by spores genus Matteuccia, genus Pteretis, Matteuccia, Pteretis - small genus sometimes included in genus Onoclea; in some classifications both genera are placed in Polypodiaceae |