ITALIC 7.0

Rostania occultata (Bagl.) Otálora, P.M. Jørg. & Wedin

Fungal Divers., 64, 1: 289, 2013. Basionym: Collema occultatum Bagl. - Comm. Soc. Critt. Ital., 1: 1, 1861.

Synonyms: Collema quadratum J. Lahm ex Körb.; Leptogium occultatum (Bagl.) Zahlbr.; Rostania quadrata (Körb.) Trevis.

Distribution: N - VG (TSB 18684), TAA (Nascimbene & al. 2007b), Piem, Lig (S-F148069). C - Tosc (Benesperi & al. 2007, Košuthová & al. 2022), Umb (Genovesi & al. 2002, Ravera & al. 2006), Laz (Ravera 2001), Abr (Ravera 2002b), Mol (Caporale & al. 2008), Sar (Zedda 2002). S - Bas (Potenza & al. 2014, Brackel 2011), Si (Grillo 1998, Grillo & Caniglia 2004, Ravera & al. 2021c).

Description: Thallus subcrustose to indistinctly subsquamulose-subplacodioid, homoiomerous, gelatinous when wet, forming a thin, effuse crust of scattered to contiguous, 120-170(-200) μm wide granules. Lobes absent or few, small and short, 150-200 µm thick (when moist), smooth, sometimes becoming coralloid and forming c. 1 mm wide rosettes. Upper surface dark olive-green to black, dull, epruinose, semi-translucent when wet. Apothecia often numerous, sessile, 0.2-0.3(-0.5) mm across, globose and perithecia-like when young, with an initially punctiform, later concave, dark red to rarely pale yellow-brown disc, an entire to lobulate thalline margin and often a paler, up to 15 µm wide parathecial ring. Thalline exciple with a simple pseudocortex; proper exciple euthyplectenchymatous, with small-ellipsoid to rectangular cells, c. 10 µm thick; epithecium brown; hymenium colourless, 80-140 µm high, I+ blue; paraphyses c. 2 µm thick at mid-level, the apical cells up to 5 µm wide; hypothecium colourless, 15-50 µm high. Asci 8-spored, cylindrical-clavate, the apex strongly thickened, the apical dome K/I+ pale blue, with a downwardly projecting K/I+ deep blue tubular structure. Ascospores subglobose when young, then more or less cubic with rounded angles and truncate ends, muriform with (4-)8-12 cells in optical view, (11-)13-16(-20) x 9-15 µm. Pycnidia immersed, globose. Conidia bacilliform, 4-5 x c. 1 µm. Photobiont cyanobacterial (Nostoc), in chains of up to 10 cells. Spot tests: all negative. Chemistry: without lichen substances.

Note: a temperate lichen found on smooth, base-rich, but not very eutrophicated bark of more less isolated broad-leaved trees (Acer, Fraxinus, Juglans, Populus) in rather humid sites, especially on basal parts of old trunks; easy to overlook and widespread, but certainly not common in Italy. It is included in the Italian red list of epiphytic lichens as “Data Deficient” (Nascimbene & al. 2013c).

Growth form: Crustose

Substrata: bark

Photobiont: cyanobacteria, filamentous (e.g. Nostoc, Scytonema)

Reproductive strategy: mainly sexual

Commonnes-rarity: (info)

Alpine belt: absent

Subalpine belt: absent

Oromediterranean belt: absent

Montane belt: extremely rare

Submediterranean belt: extremely rare

Padanian area: absent

Humid submediterranean belt: extremely rare

Humid mediterranean belt: absent

Dry mediterranean belt: absent

pH of the substrata:

1

2

3

4

5

(info)

Solar irradiation:

1

2

3

4

5

(info)

Aridity:

1

2

3

4

5

(info)

Eutrophication:

1

2

3

4

5

(info)

Poleotolerance:

0

1

2

3

(info)

Altitudinal distribution:

1

2

3

4

5

6

(info)

Predictive model

Herbarium samples

Index Fungorum GBIF

P.L. Nimis CC BY-SA 04

TSB 8252

P.L. Nimis; Owner: Department of Life Sciences, University of Trieste

Herbarium: TSB (8252)
2001/12/04

P.L.Nimis; Owner: Department of Life Sciences, University of Trieste

Herbarium: TSB (36982)
2008.02.25

P.L.Nimis; Owner: Department of Life Sciences, University of Trieste

Herbarium: TSB (36982)
2008.02.25

P.L.Nimis; Owner: Department of Life Sciences, University of Trieste

Herbarium: TSB (36982)
2008.02.25

Curtis Randall Björk – CC BY-SA 4.0

Northwest New Mexico Date: 2010-03-05 Photographed from specimen (T.T. McIntosh 9668b, Hb. McIntosh), on oak bark

Degelius G. 1954. The lichen genus Collema in Europe: Morphology, Taxonomy, Ecology. Symbolae Bot. Upsal. 13, 2: 1-499.

Degelius G. 1954. The lichen genus Collema in Europe: Morphology, Taxonomy, Ecology. Symbolae Bot. Upsal. 13, 2: 1-499.

Pier Luigi Nimis - CC BY-SA 4.0

Herbarium: TSB 8252