Caloplaca demissa (Körb.) Arup & Grube

Lichenologist, 31, 5: 428, 1999. Basionym: Placodium demissum Körb. - Parerga Lichenol.: 55, 1859.
Synonyms: Imbricaria demissa Flot. nom. inval.; Lecanora demissa (“Flot.”) Zahlbr.; Lecanora incusa (Flot.) Vain.; Olegblumia demissa; Rinodina castanoplaca (Nyl.) H. Olivier; Squamaria elaeina var. saxicola Beltr.
Distribution: N - Ven, TAA, Lomb, Piem (Valcuvia 2002, 2002b), VA (Piervittori & Isocrono 1999). C - Tosc, Laz, Sar (Nöske 2000). S - Si (Herb. Vondrák 10758).
Description: Thallus crustose-placodioid, episubstratic, firmly attached, pale to dark brown to almost black in sunny situations, often greyish-pruinose in central parts, up to 0.15 mm thick, forming regular to irregular rosettes to 1 cm in diam., several thalli often merging to cover larger surfaces. Lobes 1-1.5(-2) mm long, (0.1-)0.3-0.5(-0.8) mm wide, flat to weakly convex, towards the tips divided into 2-3 secondary lobules. Soralia mainly in the centre of thallus, laminal, at first punctiform then irregularly rounded, concave, 0.3-0.5 mm wide, finally sometimes elongated and fissure-like, brownish to brownish green, those in the central parts of thallus often coalescing. Soredia 30-50 μm thick, becoming blastidiate-isidioid., grey-brown to dark brown or brownish green. Cortex 30-40 µm thick, with a brown pigment dissolving in K and forming colourless crystals; medulla white, prosoplectenchymatous. Apothecia not observed in Italian material. Photobiont chlorococcoid. Spot tests: all negative. Chemistry: thallus with vicanicin and caloploicin.
Note: a mild-temperate to xeric subtropical species found on steeply inclined to underhanging surfaces of basic siliceous rocks sheltered from rain, both in dry-warm Alpine valleys and in the Mediterranean belt; much less bound to water seepage than Peltula euploca and ecologically related species. The species, known only as sterile, earlier positioned in the Lecanoraceae, in the genera Lecanora and Placolecanora, because of its general appearance, has a quite remote position in the Teloschistaceae and it has no supported sister lineage (see e.g. Arup & al. 2013). It was segregated in the genus Olegblumia by Kondratyuk & al. (2015), but with a wrong basionym, which makes that name illegitimate.
Growth form: Crustose placodiomorph
Substrata: rocks
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)
Subcontinental: restricted to areas with a dry-subcontinental climate (e.g. dry Alpine valleys, parts of Mediterranean Italy)
On otherwise dry surfaces with short periods of water seepage after rain

Commonnes-rarity: (info)

Alpine belt: absent
Subalpine belt: absent
Oromediterranean belt: very rare
Montane belt: extremely rare
Submediterranean belt: extremely rare
Padanian area: absent
Humid submediterranean belt: very rare
Humid mediterranean belt: rare
Dry mediterranean belt: rather rare

pH of the substrata:


Solar irradiation:








Altitudinal distribution:


Predictive model
Herbarium samples

Felix Schumm CC BY-SA 4.0
Korea, Prov. Gangwon-do, beside Maengbang beach, around Mt. Deokbong-san, Hamaengbang-ri, Gundeok-myeoun, Samcheok city, 37°23’19.57’’ N, 129°14’21.23’’ E, 4-10 m, on rocks.
Leg. K.H. Moon (14694) and H. Kashiwadani.

Curtis Randall Björk, - CC BY-SA 4.0
Vancouver Island, British Columbia, Canada

P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (10065)

P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (10005)

Manuel Gil
Spain, Canary Islands, Lanzarote