Thallus delimited, c. 37 cm (or more) diam., ± placodioid, sometimes with a narrow black edge, deeply rimose-areolate with areoles 0.32.4 mm across, ochraceous, matt or sometimes ± glossy in younger parts; prothallus not evident. In section: thallus 0.10.5 mm thick; cortex 6570 (95) ΅m thick, hyaline or upper part dilute straw-brown, hyphae densely compacted, ± overlain by a hyaline epinecral layer c. 5 ΅m thick; algal layer 70120 ΅m thick; medulla I+ blue-mauve, upto 0.4 ΅m thick, hyaline, but containing large amounts of mineral particles from the substratum giving an outward, grey to pale ochraceous appearance. Photobiont cells ± globose, 6.59.5 ΅m diam., a few seen to be dividing by binary fission; cells ± vertically arranged, together with associated mycobiont hyphae.
Apothecia lirelliform, often tightly arranged in ± stellate, or non-radiating clusters c. 1.22 mm diam., innate within the areoles, or with the margins raised above the surface layer of the thallus; lirellae elongate, serpentine and frequently branched, (0.3)0.41.8 mm long and 0.10.34 mm wide, black, but margin often coated with a rusty ochraceous pruina; disc slit-like, bordered by a black margin (upper exciple). In section, lirellae 140240 ΅m wide and 180300 ΅m tall. Exciple cupulate, dark reddish brown, K, N, 4252 ΅m thick at base, 2445 ΅m laterally, and 3595 ΅m thick at apex [margin or labium]. Hymenium 130140 ΅m tall, hyaline, without a well-defined epithecium, I+ blue. Hypothecium not well delimited from the hymenium, c. 3547 ΅m tall, mottled reddish brown. Paraphyses richly branched and anastomosed, not moniliform, 1.21.7 ΅m wide. Asci clavate, 97121 Χ 1931 ΅m, 8-spored; in K/I with an amyloid outer wall, and an apparently non-amyloid tholus [few good preparations obtained]. Ascospores (17)1931 Χ (8)912 ΅m, ellipsoid, ovoid-ellipsoid or oblong-ellipsoid, submuriform with 35 transverse septa and 411 cells in optical section; no perispore observed.
Conidiomata not seen.
Chemistry. Thallus K, C, KC, P, UV; no substances detected by TLC.
Distribution: Known only from the Juan Fernandez Islands and SW Chile.
Distribution in Google Earth
Notes: Lithographa skottsbergii is very similar to L. serpentina Coppins & Fryday known only from the type collection on Campbell Island, New Zealand (Coppins & Fryday 2006). The ascomata have the same general appearance and, presumably, ontogeny, the thallus edge is often well delimited, and both species have submuriform ascospores and an ascus dome with a non-amyloid interior. However, L. skottsbergii differs in having larger ascospores (1419 Χ 89 ΅m in L. serpentina), non-moniliform paraphyses, and an I+ blue-mauve medulla.
A new genus will probably be required to accommodate these two species Unfortunately, no fresh material of either species is available for molecular analysis, the most recent collection being made in 196970.
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