Cystopteris protusa (C. fragilis var. protusa) Posted on Feb 18, 2021 Common Name: Lowland Bladderfern, Lowland Fragile Fern, Lowland Brittle Fern, Southern Fragile Fern 6-18 inches tall by 6-18 inches spread. Part to full shade; moderately wet to medium moisture level;… Cystopteris / Ferns / Native Plants