ITALIC 8.0

Placopyrenium cinereoatratum (Degel.) Orange

Lichenologist, 41: 132, 2009. Basionym: Verrucaria cinereoatrata Degel. - Svensk Bot. Tidskr., 39: 18, 1945

Synonyms:

Distribution:

Description: Thallus crustose to subsquamulose, well-delimited, 0.2-0.6 mm thick, rimose-areolate, the areoles angular, constricted at base, 0.5-1.2 mm wide, flat to slightly convex, pale grey to mid-brown with black sides, faintly to distinctly pruinose, rarely divided by a few dark lines; when growing on Staurothele fissa the thallus is thinner, cracked and without a distinct margin. Cortex poorly differentiated, paraplectenchymatous, the cell walls often with a brown pigment, with an up to 12 μm thick but sometimes poorly developed epinecral layer; photobiont cells arranged irregularly or in weakly defined columns; lower parts of medulla (in section) with a dense brown pigment. Perithecia immersed, 0.15-0.3 mm across, the apex often visible as a small brown dot, more rarely appearing as a flat or slightly projecting black disc. Involucrellum absent; exciple brown at apex, colourless in lower part; hamathecium of periphyses and periphysoids, interascal filaments absent; hymenial gel hemiamyloid. Asci 8-spored, clavate, I-, fissitunicate, the wall thickened above with an indistinct ocular chamber, Verrucaria-type. Ascospores 1-celled, hyaline (rarely faintly brown when overmature), ellipsoid, (13-)16–21(-25.5) x (5.5-)6.5-8(-9.5) μm, the perispore thin and indistinct or absent. Pycnidia immersed, the wall colourless or faintly brown near the ostiole, multilocular, Dermatocarpon--type. Conidia simple, hyaline, bacilliform, 4-6 x c. 1.2 μm. Photobiont chlorococcoid. Spot tests: cortex and medulla K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.

Note: a facultative parasite of Staurothele fissa on siliceous rocks along streams and lakes; widespread in Western and Northern Europe but rare, with two isolated records from the Alps, but perhaps not recognised, and therefore overlooked elsewhere; to be looked for in Italy.

Growth form: Crustose

Substrata: rocks

Photobiont: green algae other than Trentepohlia

Reproductive strategy: mainly sexual

Periodically submerged (e.g. in creeks)

paras Staurothele fissa

pH of the substrata:

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Solar irradiation:

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Aridity:

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Eutrophication:

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Poleotolerance:

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Altitudinal distribution:

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Predictive model

Index Fungorum GBIF

Image uploaded by Mark Powell – CC BY-SA NC – Source: https://fungi.myspecies.info/all-fungi/placopyrenium-cinereoatratum

Image uploaded by Mark Powell – CC BY-SA NC – Source: https://fungi.myspecies.info/all-fungi/placopyrenium-cinereoatratum