ITALIC 7.0

Inoderma byssaceum (Weigel) Gray

Nat. Arrang. Brit. Plants, 1: 498, 1821. Basionym: Sphaeria byssacea Weigel - Observ. Bot.: 42, 1772.

Synonyms: Arthonia biformis (Flörke) Schaer.; Arthonia byssacea (Weigel) Almq.; Arthonia velana Jatta; Pyrenotea biformis (Flörke) A. Massal.; Pyrenotea byssacea (Weigel) A. Massal.

Distribution: N - Ven, TAA (Nascimbene & al. 2007b), Emil (Watson 2014, Fariselli & al. 2020). C - Tosc (Loppi & Frati 2006), Abr. S - Camp.

Description: Thallus crustose, mostly endosubstratic, continuous to finely rimose, very thin to evanescent, whitish to pale brown, ecorticate, usually forming large patches, without a distinct prothallus, the hyphae K/I+ pale blue. Apothecia rare, rounded, arthonioid, adnate to sessile, more or less constricted at base, 0.3-1 mm across, 90-210 µm tall, with a slightly to strongly convex, densely white-pruinose disc, without a distinct proper margin. Proper exciple reddish brown, poorly developed, 8–22 μm thick, of paraphysoidal hyphae, densely inspersed by pale granular crystals; epithecium colourless to pale grey to pale brown, inspersed with colourless crystals, 10-25 µm high; hymenium colourless to pale yellowish brown, 45-65 µm high, I+ blue/red and K/I+ blue; paraphysoids forming a loose network between the asci, wavy, 1-1.5 µm thick at base, the apical cells up to 2 µm wide; hypothecium dark brown, of intertwined, branched and anastomosing, prosoplectenchymatous hyphae embedded in a gelatinous matrix, 50-120 µm high. Asci 8-spored, clavate, semifissitunicate, without K/I+ blue tholus structures, Arthonia-type. Ascospores (2-)3-4(-5)-septate, hyaline, narrowly obovate, (11-)13-19(-23) x (4-)5-7(-8) µm, with a slightly larger apical cell, the septation microcephalic, starting in or slightly above the middle and extending downwards. Pycnidia emergent, 0.15-1.4 mm in diam., dark brown to black but thickly white-pruinose at least at the base, flattened to urceolate, with pale brown conidial masses usually protruding from the apical pore, of the Lecanactis-type of Vobis (1980), the wall paraplectenchymatous, dark brown to black, pruinose, K+ greenish black, N+ slowly orange-brown, the conidiogenous cells phialidic, of type II of Vobis (1980). Conidia bacilliform, straight, (4-)5-6 x 1-1.5 µm. Photobiont trentepohlioid. Spot tests: thallus K-, C-, KC-, P-. Chemistry: Byssaceum-unknowns, probably 2'-O-methylperlatolic acid and one accessory compound.

Note: a mild-temperate species found on very old deciduous trees with acid bark (in Italy oaks) in open woodlands, often near rivers. Most Italian records are old, and the species was included as “Regionally Extinct” in the Italian red list of epiphytic lichens (Nascimbene & al. 2013c).

Growth form: Crustose

Substrata: bark

Photobiont: Trentepohlia

Reproductive strategy: mainly sexual, or asexual by conidia and thalloconidia

In underhangs rarely wetted by rain

Commonnes-rarity: (info)

Alpine belt: absent

Subalpine belt: absent

Oromediterranean belt: absent

Montane belt: absent

Submediterranean belt: extremely rare

Padanian area: absent

Humid submediterranean belt: extremely rare

Humid mediterranean belt: absent

Dry mediterranean belt: absent

pH of the substrata:

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5

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Solar irradiation:

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5

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Aridity:

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5

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Eutrophication:

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5

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Poleotolerance:

0

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Altitudinal distribution:

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Predictive model

Herbarium samples

Index Fungorum GBIF

Liis Marmor CC BY NC -NDrapha%20corticolaHtfld.jpg http://www.eseis.ut.ee/LichenPhoto_2200/Arthonia_byssacea_l2.jpg

Holotype

Redinger, K. (1938) Arthoniaceae, Graphidaceae . In Kryptogamen-Flora von Deutschland, Österreich und der Schweiz. Band 9, 2 Abt., Part 1 (G. L. Rabenhorst, ed.): 181–404. Leipzig: Borntraeger