Byssoloma croceum Sérus. & Puntillo

in Sérusiaux, Cryptogamie, Bryol. Lichénol., 19: 204, 1998.
Synonyms:
Distribution: S - Cal (Sérusiaux 1998, Puntillo 2000).
Description: Thallus crustose, thinly episubstratic, consisting of small flattened granules, orange,-brown, brown or dirty brown-green, forming 1-3 mm wide, orbicular patches when growing on leaves, up to 3-5 mm wide when growing on bark, without a distinct prothallus. Apothecia biatorine, most abundant in corticolous specimens, rounded to clearly deformed, sometimes lobulate, clearly constricted at base, 0.1-0.3(-0.4) mm across, with a flat to convex, orange-brown to dark violet-brown disc, and a paler, thin, byssoid margin which is evident only in young apothecia. Exciple colourless, 10-15 µm wide, of loosely arranged hyphae, usually containing numerous crystals visible under polarized light; epithecium brownish, 5-8 µm thick, strongly inspersed with crystals; hymenium colourless, 30-40 µm high, without crystals; paraphyses simple or sparingly branched, the apical cells not swollen; hypothecium orange-brown, K+ purple-brown, 10-15 µm high, without crystals. Asci 8-spored, clavate, with a K/I+ blue apical dome containing a darker blue, tubular ring-structure, and an amyloid coat, Byssoloma-type. Ascospores 3-septate, hyaline, ellipsoid, 12-16 x 3-4 µm , with a thin halo. Pycnidia rare, subglobose, dirty brown, c. 0.75 µm across. Conidia biclavate to obpyriform, 3-4 x c. 1 µm. Photobiont chlorococcoid. Spot tests: thallus K-, C-, KC-, P-, UV-. Chemistry: thallus without lichen substances.
Note: a humid subtropical foliicolous species, hitherto known only from Macaronesia and Calabria, in evergreen humid forests. It is included in the Italian red list of epiphytic lichens as “Critically Endangered” (Nascimbene & al. 2013c).
Growth form: Crustose
Substrata: leaves
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
Restricted to humid-warm, oceanic areas

Commonnes-rarity: (info)

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


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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Domenico Puntillo; Owner: Domenico Puntillo
Italy