The species epithet angustata, derived from the Latin angustatus ("narrow"), alludes to the shape of the thallus lobes.

[1] Dufourea angustata is a lichen that typically forms a reddish-orange to brick orange thallus, spanning 2–3 cm in width.

The cortex of the thalline exciple (the outer layer of the apothecium) is composed of densely packed, palisade-like cells and is up to 15 μm thick.

The true exciple (the inner tissue layer of the apothecium) has a well-developed matrix, ranging from mesodermatous paraplectenchymatous to somewhat pseudoprosoplectenchymatous in structure.

It thrives on exposed and water-washed rocks such as schists, basalt, rhyolite, quartzite, and granite, particularly on outcrops and pebbles along the shoreline.