Metamelanea umbonata Henssen

Lichenologist, 21: 105, 1989
Synonyms:
Distribution: N - TAA (Pistocchi & al. 2026).
Description: Thallus crustose, homoiomerous, gelatinous when wet, episubstratic, brown-black to very dark greenish black or dark olive brown, somewhat glossy, areolate, forming up to 5 cm wide patches, the areoles 0.2-0.6 mm wide, c. 0.3 mm thick, more or less angular, obtusely wedge-shaped in section, the surface with numerous, densely aggregated, erect, 12-35 µm wide, lobule-like outgrowths containing the densely packed photobiont cells surrounded by a loose network of hyphae. Apothecia adnate, 1-7 per areole, up to 0.6 mm across, with a blackish, umbonate to gyrose disc, the umbo up to 120 µm broad and 70 µm high, a dark reddish brown proper margin, and a well-developed, entire, coronate, persistent thalline margin, proper and thalline margin often separated by a thin fissure. Thalline exciple up to 200 µm wide; proper exciple up to 20 µm wide apically, up to 10 µm wide basally, dark brown in upper part, paler in lower part; epithecium brown; hymenium colourless to brownish in upper part, 90-150 um high, K/I+ blue; paraphyses septate, sparingly branched and anastomosing, the apical cells slightly swollen; hypothecium colourless to pale brown, K/I+ blue. Asci 8-spored, long-cylindrical-clavate, thin-walled, without internal amyloid structures. Ascospores 1-celled, hyaline, broadly ellipsoid, 11-13.5 x 8-9.5 µm, thin walled. Pycnidia laminal, immersed, 110-140 µm high, 40-65 µm across, with a colourless wall. Conidia bacilliform, 2-3.5 x 1-1.5 µm. Photobiont cyanobacterial, chroococcoid, the cells surrounded by brownish gelatinous sheaths, densely aggregated in vertical columns. Spot tests: all negative. Chemistry: without lichen substances.
Note: a rare species, described from Switzerland and also known from Scandinavia, growing in seepage tracks on steeply inclined, damp faces of calciferous rocks.
Growth form: Crustose
Substrata: rocks
Photobiont: cyanobacteria, coccaceous (e.g. Gloeocapsa)
Reproductive strategy: mainly sexual
On otherwise dry surfaces with short periods of water seepage after rain

Commonnes-rarity: (info)

Alpine belt: absent
Subalpine belt: extremely rare
Oromediterranean belt: absent
Montane belt: extremely 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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Predictive model
Herbarium samples
DOLICHENS

Source: Prieto M., Westberg M, Schultz M. Herzogia 28 (1), 2015: 142–152
Westberg SL48, S


Source: Prieto M., Wedin M., Schultz M. 2024. Phylogeny, evolution and a re-classification of the Lichinomycetes. Studies in Mycology, 109: 595-655. - CC BY-NC-ND
Metamelanea umbonata, crustose, areoles angulate, thick with blackish, umbonate apothecia (Orange 15053) Scale bar: 1 mm