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Zwackhia prosodea (Ach.) Ertz

Synonyms:

Opegrapha taxicola Leight.

Opegrapha prosodea Ach.

Opegrapha viridis var. taxicola (Leight.) Leight.



Family: ROCCELLACEAE

Habitat: Oceanic zone

Description

    Thallus crustose, thin to very thin, smooth or minutely cracked, pale grey, dull white, grey-whitish, sometimes pale brown-olive tinged with green, seldom brown. Apothecia lirellate, fissure narrow and width stable during maturation, numerous, rather sessile, as laying on the thallus surface, short, straight or curved, seldom branched, 1-3 x 0.2-0.3 mm, black without pruine. Ascii 8-spored, 80-110 x 15-20 µm according to our measures. Ascospores acicular, colourless, straight or very slightly curved, 8-14 septate, surrounded with a gelatinous perispore, 50-70 x 6-8 µm according to literature, 45-65 x 7-8 (10) µm according to our measures. Infrequent pycnidia with 3 x 1 µm pycnidiospores according to our measurements. Chemical spot tests negative. Not very rare oceanic species characteristic of the dry and not wet barks of the old oaks (Quercus), but also on the barks of the old Taxus, in particular of the enclosures of the vaults, also in edge of the sea on the old Cupressus; often (at least on Quercus) in the company of Schismatomma decolorans.

Cf. Zwackhia viridis very similar although its thallus is more brownish or olive and its apothecia half-immersed and growing on smooth and humid bark of young deciduous trees.

N.B. Probably less rare than reported in the inventories because by its macroscopic appearance this species was probably confused with Arthonia atra in the absence of microscopic control.







Zwackhia prosodea Asques et spores Bleu Coton Logonna-Daoulas 17
Jacques HAINE



Zwackhia prosodea sur Quercus Plougastel-Daoulas 2
Jacques HAINE



Zwackhia prosodea Coupe apothƩcie Plougastel-Daoulas 3
Jacques HAINE



Zwackhia prosodea Asque KOH Logonna-Daoulas 4
Jacques HAINE



Zwackhia prosodea Asque Bleu Coton Logonna-Daoulas 5
Jacques HAINE



Zwackhia prosodea Asque Lugol Plougastel-Daoulas 6
Jacques HAINE



Zwackhia prosodea Coupe ƩcrasƩe KOH Logonna-Daoulas 19
Jacques HAINE



Zwackhia prosodea Spores Bleu Coton Plougastel-Daoulas 8
Jacques HAINE



Zwackhia prosodea Spores Lugol Plougastel-Daoulas 9
Jacques HAINE



Zwackhia prosodea Plougastel-Daoulas 10
Joƫl QUERELLOU



Zwackhia prosodea Plougastel-Daoulas 11
Joƫl QUERELLOU



Zwackhia prosodea Plougastel-Daoulas 12
Joƫl QUERELLOU



Zwackhia prosodea Plougastel-Daoulas 13
Joƫl QUERELLOU



Zwackhia prosodea Spores KOH Logonna-Daoulas 7
Jacques HAINE



Zwackhia prosodea Coupe lirelle KOH Logonna-Daoulas 18
Jacques HAINE



Zwackhia prosodea Logonna-Daoulas 1
Jacques HAINE



Zwackhia prosodea Coupe pycnide KOH Logonna-Daoulas 20
Jacques HAINE



Zwackhia prosodea Pycnidiospores KOH Logonna-Daoulas 21
Jacques HAINE



Zwackhia prosodea Logonna-Daoulas 14
Bernard BOUFFINIER



Zwackhia prosodea Logonna-Daoulas 15
Bernard BOUFFINIER



Zwackhia prosodea Logonna-Daoulas 16
Bernard BOUFFINIER



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