ITALIC 8.0

Thelignya obtenebrans (Nyl.) M. Schultz

in Prieto & al., Studies in Mycology, 109: 624, 2024.. Basionym: Collemopsis obtenebrans Nyl. - Flora, 68: 39, 1885.

Synonyms: Psorotichia obtenebrans (Nyl.) Forssell

Distribution: C - Tosc (TSB 30615).

Description: Thallus crustose to crustose-placodioid, rimose-areolate, usually well delimited, often with radiating marginal lobes, homoiomerous, pseudoparenchymatous throughout, the hyphae 3-6 µm thick. Areoles 0.1-0.75 mm wide, flat, smooth, contiguous, black to dark grey when dry, dark olive-brown when wet, epruinose, not granulose, the peripheral ones often elongate and radiating. Apothecia formed from a spheroid tangle of generative hyphae with ascogones and trichogynes (no pycnoascocarps), at first immersed then sessile, 1-2 per areole, 0.2-0.4 mm across, with an initially punctiform, later expanded, concave, dark brown disc surrounded by a thick, smooth, epruinose thalline margin. Proper exciple poorly differentiated, cupuliform, formed by a few anastomosing hyphae; epithecium orange-brown, 7-15 µm high; hymenium colourless, 90-100 µm high; paraphyses branched and anastomosing, with cylindrical cells, 2-3 µm thick, only slightly constricted at septa; hypothecium colourless, 30-50 µm high. Asci 8-spored, narrowly cylindrical-clavate, with a very thin wall disintegrating or opening by apical ruptures, without apical amyloid structures, Lichina-type, 60-75 x 10-15 µm. Ascospores 1-celled, hyaline, ellipsoid to subglobose, 10-12(-14) x 6-8(-9) µm. Photobiont cyanobacterial chroococcoid, single-celled with thin, yellowish brown gelatinous sheaths. Spot tests: all negative. Chemistry: without lichen substances.

Note: a southern species of sunny calcareous rocks at relatively low elevations; perhaps related to Pterygiopsis affinis.

Growth form: Crustose

Substrata: rocks

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

Reproductive strategy: mainly sexual

On otherwise dry surfaces with short periods of water seepage after rain

Poorly known taxon in need of further study

Commonnes-rarity: (info)

Alpine belt: absent

Subalpine belt: absent

Oromediterranean belt: absent

Montane belt: absent

Submediterranean belt: rare

Padanian area: absent

Humid submediterranean belt: very rare

Humid mediterranean belt: very rare

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

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

Herbarium: TSB (30615)
2003/03/12
identification not certain