Definition of bladder fern in US English:

bladder fern

noun

  • A small delicate fern with rounded spore cases, growing on rocks and walls. Bladder ferns are native to both Eurasia and North America.

    Genus Cystopteris, family Dryopteridaceae: several species

    Also called brittle fern
    • ‘Berry bladder ferns and columbine thrive in shaded parts, while baby lip fern and shad bush bask on sunny rock faces.’
    • ‘Bulbet bladder fern, brittle bladder fern, and slender cliff brake grow among the outcrops here.’
    • ‘More than 30 species of ferns have been identified here, including hay-scented, New York and bladder ferns.’