| bladder fern | (n) any fern of the genus Cystopteris characterized by a hooded indusium or bladderlike membrane covering the sori |
| brittle bladder fern | (n) delicate fern widely distributed in North America and European having thin pinnatifid fronds with brittle stems, Syn. brittle fern, fragile fern, Cystopteris fragilis |
| mountain bladder fern | (n) fern of rocky mountainous areas of hemisphere, Syn. Cystopteris montana |
| bulblet fern | (n) North American fern often bearing bulbils on the leaflets, Syn. berry fern, bulblet bladder fern, Cystopteris bulbifera |