Description: A foliose lichen genus in the Parmeliaceae with 11 species. - "Thallus foliose, up to 20 cm broad, with often ascending and undulated lobe margins. Upper surface often shiny, grayish-white to greenish-brown, marginally often dark brown, and often net-like wrinkled, pseudocyphellae sometimes present, elongated, on ridges, often as a pre-stage of an area where later on isidia are developed, faintly elongated maculae present, isidia or soralia present in some species, on margins or laminal on ridges. Cortex in several species IKI+ bluish-lilac. Lower surface creamy white to shiny brown at the margin or shiny blackish at the center, often mottled, some species with white, punctiform to slightly elongated, slightly raised pseudocyphellae. Apothecia rare, up to 4 cm in diameter, marginal or submarginal, with a brown sometimes perforate disc. Asci of the Lecanora-type, 8-spored. Spores single-celled, colorless, rather small 3.5-10.0 µm in length, ellipsoid or subglobose. Pycnidia rare, immersed, marginal. Conidia often cited as "bacilliform" or "rod-shaped", but at least in Platismatia erosa and P. glauca bottle-shaped (sublageniform sensu Thell 1995: 253) to slightly "bowling pin-shaped", 4.0-7.8 x 0.85-1.3 µm. Chemistry: Atranorin, chloratranorin (see Elix & Scholz 1995-2002), fatty acids (caperatic acid syndrome in most specimens, rarely substituted by jackinic acid syndrome [in P. erosa], fumarprotocetraric acid, only in P. lacunosa, pannaric acid [in P. erosa], pseudoplacodiolic acid in P. glauca, see Elix & Scholz 1995-2002, yellow pigment(s?) (p.p. in P. erosa, P. herrei, P. interrupta, P. regenerans)" (Obermayer & Randlane 2012: 52).