Heterodea is a small genus of lichen-forming fungi in the family Cladoniaceae. It comprises two species. The two species form flat, leafy thalli and grow on soil, rock, and plant debris in open habitats in southern Australia, where they can resemble members of the related genus Cladia. The genus has had a complicated taxonomic history, having been variously merged with and separated from the related genus Cladia as molecular studies have progressively clarified the relationships within the Cladoniaceae.

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