Cat. Lich. Univers. 8: 490 (1932).

Basionym: Lichen decussatus Vill., Hist. Pl. Dauphiné 3, 2: 964 (1789).

Distribution: Cosmopolitan, known from both polar regions and many high mountain area (Topham & Walker 1982: 74). Database

Taxonomy: The species Umbilicaria decussata represents a recent pleomorphic species in the process of splitting up into at least four different lineages with ancestral polymorphisms still present (Davydov et al. 2017: 19).

Note: Davydov et al. (2017) showed, that U. decussata and U. polaris should be treated as one species.