ITALIC 7.0

Usnea viktoriana P.Clerc & Otte

Lichenologist 50: 514, 2018

Synonyms:

Distribution: N - TAA (Clerc & Otte 2018).

Description: Thallus fruticose-filamentous, greenish, shrubby to subpendulous, up to 15 cm long, anisotomic dichotomously branching, the basal branches spreading laterally. Main branches cylindrical or slightly swollen, papillose, sometimes short and dividing quickly into secondary branches (thallus shrubby), or remaining clearly visible (thallus subpendulous); segmentation inconspicuous, with 0.6-2 mm thick annulations, the segments cylindrical or slightly swollen, the base blackened on 1-3 mm, usually thinner at the contact point with the bark and then slightly enlarging towards the main branches; lateral branches not constricted at attachment point, with or without fibrils. Foveolae, maculae, tubercles and pseudocyphellae absent; papillae always present on main branches, numerous, short verrucose to subcylindrical, 35-50 x 50-90 μm; fibrils few and scattered to rarely numerous on young branches. Soralia developing on the apices of thin lateral branches, punctiform when young, later forming larger, irregular, nodulose aggregates, usually even with cortex, slightly excavate when isidiomorphs are shed, with numerous isidiomorphs and fragile, often fasciculate, 0.25-0.7 mm long isidiofibrils. Cortex matt, moderately thick (6-13 % of total branch thickness); medulla dense, white, moderately thin to moderately thick (10-30.5 %); central axis white, moderately thin to moderately thick (26-62 %); ratio axis/medulla: (0.8-)1-2.8(-6.2). Apothecia rare, lecanorine, subterminal, up to 5 mm across. Asci 8-spored, Lecanora-type. Ascospores 1-celled, hyaline, ellipsoid, c. 8 x 5 µm. Photobiont chlorococcoid. Spot tests: cortex K-, C-, KC-, P-; soralia K- or K+ reddish orange, C- or C+ red, KC- or KC+ red, P-. Chemistry: usnic acid in cortex; the most common chemotype contains (in the soralia) alectorialic acid and 5,7-dihydroxy-6-methylphthalide (soralia K-, C+ and KC+ red), other chemotypes may contain salazinic (main) and barbatic (accessory) acids, or no lichen substances.

Note: a recently-described species (type from South Tyrol), widespread from Central Europe to the Caucasus, with optimum in oroboreal forests.

Growth form: Fruticose filamentous

Substrata: bark

Photobiont: green algae other than Trentepohlia

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

Subcontinental: restricted to areas with a dry-subcontinental climate (e.g. dry Alpine valleys, parts of Mediterranean Italy)

Commonnes-rarity: (info)

Alpine belt: absent

Subalpine belt: rather 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:

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

Index Fungorum GBIF

Source: Clerc P., Otte V. 2018. Usnea viktoriana (Ascomycota, Parmeliaceae), a new European taxon of the Usnea barbata-dasopoga group, with a key to the shrubby-subpendulous sorediate Usnea species in Europe. Lichenologist, 50, 5: 513-527.

holotype