ITALIC 8.0

Placopyrenium formosum Orange

Lichenologist, 41: 135, 2009

Synonyms:

Distribution:

Description: Thallus crustose, episubstratic, starting the life-cycle on Aspicilia aquatica (damaging the host), 130-400 μm thick, areolate, the areoles discrete, separated by deep cracks, at first c. 0.2-0.4 mm wide, then up to 1.2 mm wide, flat to slightly convex at maturity, slightly constricted at base, grey-brown to brown with black flanks, sometimes pruinose, often developing on a brown hypothallus. Cortex weakly developed, paraplectenchymatous, with a brown pigment; photobiont cells arranged irregularly or in weakly defined columns; lower parts of medulla (in section) patchily brown-pigmented. Perithecia immersed, 1-22 per areole, the apex black, flat or slightly convex, up to 180 μm across. Exciple 140-220 μm in diam., colourless or brown in lower part, thickened and brown in upper part; involucrellum absent; 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 or rarely faintly brown when overmature, oblong-ellipsoid, (14-)17.5-22.5(-28) x (7-)8-10(-11) μm, with a 1-1.5 μm thick, compact perispore. Pycnidia laminal, immersed, multilocular, Dermatocarpon-type. Conidia simple, hyaline, bacilliform, 3.7-5.3 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 Aspicilia aquatica on siliceous rocks along streams; widespread in Western and Northern Europe but rare, with a few records from the Western Alps (France); 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 Aspiciia aquatica when young

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