Lichenologist 31, 5: 428 (1999).
Basionym: Placodium demissum Flot. ex Körb., Parerga lichenol. (Breslau) 1: 55 (1859).
Lectotype: Germany, Lorch, Zwackh: Exs. Zwackh L. 187 (UPS - lectotype selected by Arup & Grube 1999: 428).
Type locality: Germany, Baden-Württemberg, Reg.-Bez. Stuttgart, Landkreis Ostalbkreis, Lorch, 288 m, Zwackh (UPS - lectotype). Lectotypification by Arup & Grube (1999: 428)
Barcode: Data lacking.
Coordinates: 48°48'N, 9°41'E.
Thallus: crustose, elongate lobed, margin abrupt at edge, with elongated lobes 1-1.5 mm long, 0.2-0.4 mm wide; prothallus absent; surface brown, smooth, sorediate; soredia granular, in delimited, marginal soralia on lobe tips; cortex cellular, 30-40 µm thick, granules absent; medulla prosoplectenchymatous, without granules. Apothecia absent. Pycnidia unknown (Wetmore 2007: 195).
Photobiont: Green alga.
Chemistry: Thallus K-, H-, 10%N-, cN-, C-. No lichen substances (Wetmore 2007: 195).
Ecology: On non-calcareous rocks (xxx). Vertical or overhanging base-rich siliceous rocks (Vondrák & Hrouzek 2006: 7).
Molecular data: Genbank
Distribution: Europe, North America.
Note: Caloplaca demissa has a thallus with elongated lobes that may become slightly pruinose and with laminal punctiform soralia. It may at first look like a Koerberia but that has cyanobacteria instead of green algae in the thallus (Wetmore 2007: 195). "Caloplaca albolutescens, C. atroflava, C. demissa, C. erythrocarpa, C. soralifera, C. teicholyta, C. xerica are clearly related to the genus Pyrenodesmia, but more sequence data are needed to resolve the relationship of this genus to the C. xerica group and C. demissa" (Arup et al. 2013: 74).
"Caloplaca demissa has generally been cited as being described by Flotow (1850). However, in this publication the name Imbricaria demissa Fw. is followed by 'ad int.', which means that this name was not validly published. Five years later he describes the species under the same name, in Körber (1855). Unfortunately, Körber also cites Parmelia elaeina Spr. in Flora Halensis (Sprengel 1832: 529). In Sprengel's flora, Parmelia elaeina Ach. is listed, which is Vestergrenopsis elaeina (Moberg 1977). Thus, the name Imbricaria demissa Flot. is illegitimate. However, in Körber (1859-1865) the name Placodium demissum is used and Körber (1855) is cited. This name may be seen as a new name (Art. 58.3), which is taken up by us and combined into Caloplaca. In the description of I. demissa by Flotow (in Körber, 1855), cited by Körber (1859-1865), Zwackh's lichen exsiccate no. 187 ('Exs. Zw. L. 187') was listed and the specimen in UPS of this exsiccate has been chosen as lectotype" (Arup & Grube 1999: 428).
Baden-Württemberg, Reg.-Bez. Stuttgart, Landkreis Ostalbkreis, 288 m