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 distinguishable, but sometimes tinly episubstratic and appearing as dark brown to reddish brown or grey flecks. Perithecia scattered, black, subconical to globose, projecting to half-immersed, often depressed near the ostiole, 0.15-0.3(-0.5) mm in diam. Involucrellum absent; exciple dark throughout, more or less cellular; hamathecium of richly branched and anastomosed pseudoparaphyses, the hymenial gel I-. Asci 8-spored, ovoid to subcylindrical, usually stalked, with two functional wall layers, K/I-, the wall thickened above, with an ocular chamber, fissitunicate, with a distinct extruded rostrum at dehiscence. Ascospores 1-septate but sometimes with additional pseudosepta, hyaline, ovoid to ovoid-fusiform, both cells of similar shape and size, 20-30(-33) x (7.5-)8.5-12 µm. Pycnidia black, immersed, the conidiogenous cells cylindrical, phialidic. Photobiont cyanobacterial, the cells usually abundant, orange or blue-green, up to 12 µm wide. Spot tests: all negative. Chemistry: without lichen substances.
Note: on steeply inclined to vertical surfaces of permanently damp or moist limestone or base-rich siliceous rocks; widely distributed in the Holarctic region, but not common; reported from South Tyrol and Sicily, the latter record requires confirmation.
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:


Solar irradiation:








Altitudinal distribution:


Predictive model

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.