Usnea cornuta Körb.

Usnea cornuta Körb.

Parerga Lichenol.: 2, 1865.

Synonyms: Usnea confusa Asahina; Usnea constrictula Stirt.; Usnea inflata (Duby) Motyka; Usnea inflata var. cornuta (Körb.) Clauzade & Cl. Roux; Usnea intexta Stirt.; Usnea subpectinata Stirt.

Distribution: N - Frl, TAA (Nascimbene & al. 2007b), Lig. C - Tosc. S - Camp, Cal (Brackel & Puntillo 2016).

Description: Thallus fruticose-filamentous, greenish, usually shrubby, 3-7(-10) cm long, the branching sympodial, mainly anisotomic-dichotomous with divergent branches. Main branches tapering to fusiform, with numerous annular cracks which divide the branch into cylindrical to sausage-like, terete segments, the base pale to black; lateral branches distinctly constricted at attachment point, the terminal branches arranged at right angles to the secondary branches. Papillae and tubercles few to numerous, most dense on secondary branches; fibrils irregularly distributed but usually numerous on main branches close to the basal part, spinulose, up to 3 mm long. Soralia most numerous on terminal branches (last third of thallus length), crowded (30-50 soralia/mm2), mainly developing from the cortex on secondary and terminal branches, flat and irregular in outline, initially punctiform (50-200 µm across) and occupying less than the half of the diameter of the branch, but later often confluent and resembling a single large soralium, often with 0.1–0.2 mm long, clustered isidiomorphs when young. Cortex thin to moderately thick (5–9% of total branch thickness), vitreous in longitudinal section; medulla heterogeneous, with a narrow compact ring below the cortex, otherwise lax to dense, rather thick (25–37%), white; central axis white to pale orange or pink, thin to moderately thick (15–35%); ratio axis/medulla ranging between 0.4 and 1.2. Apothecia very rare, lecanorine, to 5 mm across. Asci 8-spored, Lecanora-type. Ascospores 1-celled, hyaline, ellipsoid. Photobiont chlorococcoid. Spot tests: cortex K-, C-, KC-, P-; medulla K+ yellow, orange or blood-red, rarely K-, C-, KC-, P+ yellow or orange, very rarely P-. Chemistry: usnic acid in cortex; the medulla of the most frequent chemotype with stictic acid, variable amounts of norstictic acid, plus several accessory substances of the stictic acid complex; a rare chemotype contains salazinic and constictic acids, and a very rare chemotype is devoid of medullary substances.

Note: a chemically and morphologically variable epiphytic species also occurring on siliceous rocks, restricted to damp sites with frequent fog, mostly in the montane belt. It is included in the Italian red list of epiphytic lichens as “Endangered” (Nascimbene & al. 2013c).

Growth form: Fruticose filamentous

Substrata: bark and rocks

Photobiont: green algae other than Trentepohlia

Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)

Restricted to humid-warm, oceanic areas

Commonnes-rarity: (info)

Alpine belt: absent

Subalpine belt: absent

Oromediterranean belt: absent

Montane belt: very rare

Submediterranean belt: absent

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

Tiiu Tõrra; Owner: Tiiu Tõrra - Institute of Ecology and Earth Sciences, University of Tartu, Estonia

Tiiu Tõrra; Owner: Tiiu Tõrra - Institute of Ecology and Earth Sciences, University of Tartu, Estonia

Tiiu Tõrra; Owner: Tiiu Tõrra - Institute of Ecology and Earth Sciences, University of Tartu, Estonia

Tiiu Tõrra; Owner: Tiiu Tõrra - Institute of Ecology and Earth Sciences, University of Tartu, Estonia

Tiiu Tõrra; Owner: Tiiu Tõrra - Institute of Ecology and Earth Sciences, University of Tartu, Estonia

Tiiu Tõrra; Owner: Tiiu Tõrra - Institute of Ecology and Earth Sciences, University of Tartu, Estonia

Tiiu Tõrra; Owner: Tiiu Tõrra - Institute of Ecology and Earth Sciences, University of Tartu, Estonia

Tiiu Tõrra; Owner: Tiiu Tõrra - Institute of Ecology and Earth Sciences, University of Tartu, Estonia

Tiiu Tõrra; Owner: Tiiu Tõrra - Institute of Ecology and Earth Sciences, University of Tartu, Estonia

Tiiu Tõrra; Owner: Tiiu Tõrra - Institute of Ecology and Earth Sciences, University of Tartu, Estonia

Tiiu Tõrra; Owner: Tiiu Tõrra - Institute of Ecology and Earth Sciences, University of Tartu, Estonia

M.Wickramasinghe; Owner: M.Wickramasinghe

M.Wickramasinghe; Owner: M.Wickramasinghe

Bernard Bouffinier - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=660&lang=en

France, Camaret

Bernard Bouffinier - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=660&lang=en

France, Camaret

Bernard Bouffinier - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=660&lang=en

France, Le Relecq

Bernard Bouffinier - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=660&lang=en

France, Hôpital-Camfrou

Bernard Bouffinier - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=660&lang=en

France, Hôpital-Camfrou

Michel David - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=660&lang=en

France, Roc'h Cléguer

Michel David - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=660&lang=en

France, Roc'h Cléguer

Alain Gerault - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=660&lang=en

France, Cranou

Alain Gerault - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=660&lang=en

France, Huelgoat

Alain Gerault - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=660&lang=en

France, Landevennec, Moulin Mer

Alain Gerault - Source: http://www.lichensmaritimes.org/index.php?task=fiche&lichen=660&lang=en

France, St. Herbot

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