Sarcogyne brunnea is a species of saxicolous and terricolous (rock- and ground-dwelling), crustose lichen in the family Acarosporaceae.

[2] Sarcogyne brunnea is identifiable by its contiguous angular areoles that are up to 1.5 mm in diameter and separated by deep fissures.

This lichen has a heavily pruinose surface, with the uppermost layer bearing a dark reddish-brown to lighter brown colour.

Unlike S. crustacea, the thallus of S. brunnea is areolate, brown when wetted, and its algal layer is disrupted by hyphal bundles.

It differs from S. brunnea in having a thallus comprising small patches of overlapping squamules, shorter conidia (2–3 vs. 4–5 μm), no branching of its paraphyses, and an algal layer that is not interrupted by distinct hyphal bundles.