Its species epithet suggests a close morphological similarity to Peltula marginata but with distinct differences noted in its physical and reproductive structures.

The holotype was collected in Beijing's Dayangshan National Forest Park at an elevation of 390 m (1,280 ft), where it was found growing on soil on the surface of a rock.

[1] The thallus of Peltula submarginata is saxicolous, meaning it grows on rocks, and has a squamulose-subfruticose form—appearing scale-like initially and developing a stalk or umbilicus-like attachment to the substrate.

The algal layer is substantial, encircling the perimeter of the squamules, and the medulla contains sparse hyphae with significant hollow areas, providing structure and perhaps nutrient storage.

[1] Peltula submarginata is typically found on sun-exposed sandstone faces, predominantly in areas where other lichens are absent, suggesting a specific ecological niche.