ITALIC 8.0

Pycnora xanthococca (Sommerf.) Hafellner

in Hafellner & Türk, Stapfia, 76: 158, 2001. Basionym: Lecidea xanthococca Sommerf. - Suppl. Fl. Lapp.: 154, 1826,

Synonyms:

Distribution:

Description: Thallus crustose, episubstratic, areolate, the areoles up to 0.7(-1.2) mm wide pale grey to yellowish brown, dull. Cortex up to 15 µm thick, of thin-walled hyphae; medulla white, I-. Apothecia frequent, lecideine, black, epruinose, up to 0.8(-1.2) mm across, with a flat disc and a raised, persistent, often flexuose proper margin. Proper exciple of closely conglutinated hyphae, brownish black in outer part, dark brown within, K+ violet, N-; epithecium greenish or brownish green, without crystals, K+ violet, N-; hymenium colourless, 55-70 µm high; paraphyses sparingly branched and anastomosing, the apical cells hardly swollen; hypothecium brown. Asci 8-spored, broadly clavate, with a well developed, amyloid tholus containing an ocular chamber and a broad axial mass, Lecanora-type. Ascospores 1-celled, hyaline, ellipsoid, (7-)8-12(-13) x (3-)4-6(-7) µm. Pycnidia usually numerous, with a dirty green wall reacting K-, N+ violet. Conidia subglobose to broadly ellipsoid, 2.5-4 x 1.5-3 µm, 1.2-1.7 times as long as wide. Photobiont chlorococcoid. Spot tests: cortex and medulla K+ yellow, C+ red, KC+ red, P+ yellow, UV-. Chemistry: alectorialic acid and an unidentified substance.

Note: closely related to P. praestabilis, mainly differing in the subglobose conidia, found on wood of snags. It is widespread throughout the boreal zone, with a few records from the Alps (Austria, Germany), all of them on P. sylvestris, which however need confirmation. To be looked for in the Italian Alps.

Growth form: Crustose

Substrata: bark and lignum

Photobiont: green algae other than Trentepohlia

Reproductive strategy: mainly sexual

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

DOLICHENS

Einar Timdal - Source: http://nhm2.uio.no/lav/web/index.html - CC BY-NC

Leif Stridvall - Source: http://www.stridvall.se/la/galleries.php