Membranipora is a genus of bryozoan in the family Membraniporidae. A typical example is the widely distributed species Membranipora membranacea that commonly encrusts seaweeds, particularly fronds of the kelps Laminaria digitata, L. hyperborea, and Saccorhiza polyschides. Colonies of M. membranacea show different forms of polyphenism as spines, tower zooids, chimneys and stolons.