Biatoridium is a genus of lichen-forming fungi of uncertain familial, ordinal, and class placement in the Ascomycota. The genus was established in 1860 by Gustav Wilhelm Körber and contains three recognised species. These lichens form thin, greenish to grey crusts that appear as a fine dusting on rock or bark surfaces. After being neglected for decades, the genus was resurrected in 1994 and is characterised by its pale yellow-brown fruiting bodies and spherical spores.

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