Arthonia navasiana Etayo

Guineana, 16: 38, 2010.
Description: Thallus inapparent, not lichenized, developing inside the thalli of Lepraria-species. Apothecia arthonioid, black but often white-pruinose, often surrounded by a whitish thalline halo whose hyphae react I+ red, K/I+ blue, at first flat, then strongly convex and often hemispherical, usually immersed in the host thallus, 0.1-0.35 mm across, without a proper margin. Proper exciple not developed; epithecium dark brown to brown-black, K+ dark olive green, c. 10 μm high; hymenium pale yellow, 45-50 μm high, K+ greenish, I+ red, K/I+ blue; paraphysoids branched and anastomosing, brown in upper part, 2-3 μm thick, the apical cells slightly capitate; hypothecium colourless, I+ red, K/I+ blue. Asci 8-spored, clavate, semi-fissitunicate, with a large apical dome, an ocular chamber, and a distinct K/I+ ring-structure in tholus. Ascospores 3-septate, not constricted at septa and with the central cell slightly larger, hyaline, ellipsoid, 15-17 x 5-6 μm, with a c. 1 μm thick perispore reacting I+ red. Photobiont absent. Spot tests: K-, C-, KC-, P-. Chemistry: without lichen substances.
Note: a lichenicolous fungus developing on the thalli of Lepraria-species; described from Spain, to be looked for in Italy.
Growth form: Lichenicolous fungus
Reproductive strategy: mainly sexual
In underhangs rarely wetted by rain
paras Lepraria-species

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Predictive model