Pseudephebe minuscula is a species of fruticose lichen in the family Parmeliaceae. In North America, it is known colloquially as coarse rockwool. It has an antitropical distribution.
The lichen has a dark brown to almost black filamentous thallus, comprising individual cylindrical branches, closely attached to the rock substrate, often flattened, measuring 0.2–0.5 mm thick. It is common in windswept arctic and alpine environments, where it grows on granitic rocks and pebbles.