Ionaspis lacustris forme sur métal (fer).

       This form occurs on the rusty iron of metal constructions near waterways (here on a rusty iron beam, periodically flooded from an old bridge). The thallus is strongly fragmented due to the fall of the rust plates which lead to fragments. Almost always accompanied by Scoliciosporum umbrinum more usual on this kind of substrate, also accompanied by Lecidea lithophila forme sur métal (fer).