ITALIC 8.0

Opegrapha opaca Nyl.

Bot. Notiser, 10-11: 161, 1853.

Synonyms:

Distribution:

Description: Thallus not apparent, the apothecia developing on the thallus of the host lichens. Apothecia aggregated into dense wart-like, (0.2-)0.3-0.8(-1) mm wide and 0.1-0.2 mm tall clusters of 2-6, the individual apothecia often difficult to observe, black, epruinose, lirelliform, simple or shortly 1-2-furcate, with a slit-like to widely expanded disc, 0.3-0.4 x (0.12-)0.15-0.2(-0.3) mm. Proper exciple well developed, entire, 14-30 μm thick laterally, dark brown to black-brown, K-; epithecium brownish, 19-24 μm high, and I+ blue rapidly turning red; hymenium colourless, 48-55 μm high, I+ red to reddish brown, K/I+ blue; paraphyses sparingly branched, 1.4-2 μm thick at mid-level (in K), the apical cells slightly swollen, to 3.4 μm wide, covered in abundant minute brown granules; subhymenium brownish, 12-15 μm high, K-. Asci 4-6-spored, broadly clavate, fissitunicate, with a K/I+ blue ring around the top of the ocular chamber, 42-50 x (11.5-)12.5-14.5 μm. Ascospores (1-)3-septate, the upper cells often slightly larger than the lower cells, long remaining hyaline and measuring (12.5-)13.4-15.3(-17.3) x (3.4-)3.8-4.8 μm, overmature ones turning brown and up to 19 x 6 μm, sometimes with a c. 1 μm thick gelatinous perispore, the pigmented wall without brown granules. Pycnidia c. 80 μm across, immersed, with a dark brown wall, the conidiogenous cells elongate-ampulliform, 10-15 × c. 2 μm, Conidia simple, ellipsoid, hyaline, 3-4 × c. 1 μm. Photobiont absent. Spot tests: all negative. Chemistry: without lichen substances.

Note: a recently-resurrected lichenicolous fungus growing on the thalli of Verrucaria nigrescens and V. viridula, known from several sites in Western Europe, Spain (where it is often common) and Israel. To be looked for in Italy.

Growth form: Lichenicolous fungus

Substrata: rocks

Reproductive strategy: mainly sexual

paras Verrucaria nigrescens and V. viridula

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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Predictive model

Source: Coppins BJ, Kondratyuk SY, Etayo J, Cannon PF. Notes on lichenicolous species of Opegrapha s. lat. (Arthoniales) on Arthoniaceae and Verrucariaceae, with a key to British and Irish lichenicolous Opegraphaceae. The Lichenologist. 2021;53(2):159-169.