Another of the challenging-to-me ferns along the Niagara Escarpment. Based on the green stipe and the form, by comparison to other nearby photos, perhaps this is Fragile Fern (Cystopteris fragilis). Was growing on moss-covered dolomite boulder, at the base of the Niagara Escarpment, Bruce's Caves Conservation Area, Wiarton, May 16/18. Note the sequence of photos illustrates the various stages of emergent growth.