Pyrenodesmia erodens (Tretiach, Pinna & Grube) Søchting, Arup & Fröden
Basionym: Caloplaca erodens Tretiach, Pinna & Grube in Mycological Progress. 2(2): 129, 2003.
Type: Italia, Abruzzo, prov. L’ Aquila, Rovere, 2001, Tretiach and Pinna (TSB 34131-holotype).
Original discription: Tretiach, Pinna & Grube in Mycological Progress. 2(2): 129, 2003.
Thallus crustose, orbicular, up to 6–8 cm diam. in the central part euendolithic (sensu GOLUBIC, FRIEDMAN & SCHNEIDER 1981), ecorticate, sorediate, bluish-grey to violaceous, depressed, delimited at the periphery by a whitish, K-, epilithic, obscurely lobate prothallus, c. 0.25–0.50(0.80) mm thick. Photobiont green, protococcoid, cells 13.4–15.7–18.0(23) μm diam (n=50). Soralia diffuse on the thallus surface, consisting of grey, K+ violaceous soredia, c. 43–56–69(75) μm diam., formed by small, irregular clusters of photobiont cells surrounded by appressed, inflated hyphal cells, c. 6–7(8) x 4–5 μm which emerge from the rock surface. Ascomata apothecia (in Iranian specimens not found), see more info in Tretiach, Pinna & Grube in Mycological Progress. 2(2): 129, 2003: extremely rare, slightly pruinose, marginate, often irregularly shaped or immature, up to c. 0.2–0.25–0.3(0.4) mm diam.; disc bluish-grey to almost black, thalline margin present. Exciple distinct, thick, coherent in K, formed by strands of hyphae with irregularly ellipsoidal cells; outer part of the exciple dark grey or grey-green, inner part of the exciple with minute crystals persisting in N. Hymenium up to 60–70 μm high, I+ strongly blue. Hypothecium hyaline. Hamathecium of paraphyses, generally simple or slightly branched, apices swollen, up to 4–5 μm diam., pigmented as the outer part of the excipulum. Asci (4)6–8-spored, clavate, Teloschistes-type. Ascospores hyaline, polardiblastic, non-halonate, ellipsoid, 10–11–12(19) x 6– 7.0–8(9) μm (n = 39; 20 apothecia examined). Conidiomata unknown.
Chemistry Grey, acetone-insoluble pigment of epithecium, outer layer of excipulum and exposed parts of thallus K+ violaceous, C+ red-violet, N+ vivid violaceous (Sedifolia-grey sensu MEYER & PRINTZEN 2000: 581). No lichen substances detected by TLC.
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