Rimularia is a genus of lichen-forming fungi in the family Trapeliaceae. Established by the Finnish lichenologist William Nylander in 1868 from specimens collected on granitic rocks in France, the genus comprises 14 accepted species as of 2025. These rock-dwelling lichens form thin, crust-like growths that range from reddish-brown to dark olive-brown in colour and produce small black fruiting bodies with distinctive branched internal structures.

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