Collemopsidium caesium (Nyl.) Coppins & Aptroot

Lichenologist, 40: 368, 2008. Basionym: Verrucaria caesia Nyl. - Bot. Not.: 162, 1853.
Synonyms: Arthopyrenia caesia (Nyl.) Zahlbr.; Arthopyrenia nylanderi (Hepp) Riedl; Leiophloea caesia (Nyl.) Trevis.; Leiophloea nylanderi (Hepp) Trevis.; Pseudarthopyrenia caesia (Nyl.) Keissl.; Pyrenocollema caesium (Nyl.) R.C. Harris; Sagedia nylanderi Hepp
Distribution: N - TAA. S - Si (Grillo & al. 2007).
Description: Thallus crustose, mostly endosubstratic and hardly distingushable, but sometimes reaching the surface as small dark brown flecks. Perithecia scattered, black, subconical to globose, sessile to half-immersed, often depressed dear the ostiole, 0.15-0.5 mm across. Involucrellum absent; perithecial wall dark brown, more or les cellular; hamathecium of richly branched and anastomosed pseudoparaphyses, the hymenial gel I-. Asci 8-spored, elongate-clavate to subpyriform, I-, bitunicate and fissitunicate, with an ocular chamber. Ascospores hyaline, ovoid to ovoid-fusiform, 1-septate but sometimes with additional pseudosepta, one cell usually longer than the other, 20-30(-33) x (7.5-)8.5-12 µm. Pycnidia black, immersed. Photobiont cyanobacterial (Hyella). Spot tests: all negative. Chemistry: no lichen substances.
Note: a species with a mostly endolithic thallus (forming dark brown thin patches only on non-calcareous rocks), and with more or less sessile ascomata, found on steeply inclined to vertical surfaces of permanently damp or moist limestones or base-rich siliceous rocks; widely distributed in the Holarctic region, but not common.
Growth form: Crustose endolithic
Substrata: rocks
Photobiont: cyanobacteria, filamentous (e.g. Nostoc, Scytonema)
Reproductive strategy: mainly sexual

Commonnes-rarity: (info)

Alpine belt: absent
Subalpine belt: very rare
Oromediterranean belt: absent
Montane belt: very rare
Submediterranean belt: absent
Padanian area: absent
Humid submediterranean belt: absent
Humid mediterranean belt: absent
Dry mediterranean belt: absent


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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Source: Keissler K. von 1938. Pyrenulaceae, Mycoporaceae, Coniocarpineae. In: Rabenhorst G L: Kryptogamen-Flora von Deutschland, Österreich und der Schweiz. 2nd, IX, Die Flechten, Abt. 1, 2. Gebr. Borntraeger, Leipzig, pp. 1-846.