First recognised in 1937 and formally described by the Swedish lichenologist Rolf Santesson in 1992, it is distinguished by its dark brown thallus that forms rosettes up to 10 mm in diameter bearing characteristic black ridges and warts.

The species inhabits the intertidal zone, particularly on siliceous rocks, where it commonly associates with barnacles and other marine lichens.

At the thallus periphery, these ridges form a radiating pattern and appear flattened, while in the central regions they become more irregular.

These perithecia measure 0.1–0.5 mm in diameter and are prominently displayed, with an irregularly somewhat globose shape featuring a flattened to concave top that can sometimes appear deeply urceolate.

The internal structure reveals a thallus thickness of 20–50 μm, composed primarily of vertical rows of angular to rounded cells.

It shows a strong preference for siliceous seashore rocks, particularly those composed of schist or granite, though it occasionally occurs on calcareous substrates.

In the Pacific, it has been documented at several locations along the western coasts of North and South America, including California (USA), Peru, and Chile.

[2] In its typical habitat, P. elegans frequently grows in association with barnacles – specifically Semibalanus balanoides in Norwegian waters and Chthamalus species in more southerly regions.