ITALIC 7.0

Placynthium posterulum (Nyl.) Henssen

in Crzeika & Czeika, Herzogia 20: 44, 2007.. Basionym: Pterygium posterulum Nyl. - Flora, Regensburg, 58: 7, 1875.

Synonyms:

Distribution: N - Lomb (Anzi Lich. Lomb. 442: Czeika & Czeika 2007).

Description: Thallus subcrustose-placodioid, olive-brown to brown-black, sometimes pruinose especially at lobe-tips, without a distinct pro- or hypothallus (in section colourless to pale brown in lower part, never bluish), forming regular to irregular, often confluent 3-9 mm wide rosettes. Central parts of thallus consisting of cylindrical to granulose, densely packed, erect outgrowths which often fall off, leaving semi-circular rings of marginal lobes; marginal lobes up to 1 mm long and 0.09-0.15 mm wide, terete, usually separate, rather loosely attached by colourless to brownish rhizohyphae. Upper surface of lobes with densely packed, parallel hyphae, the photobiont cells mostly concentrated near the surface; central parts of lobes with a more or less well-developed hyphal strand. Apothecia and pycnidia unknown. Photobiont cyanobacterial, Scytonema-like. Spot tests: all negative. Chemistry: without lichen substances.

Note: a poorly known species found on steeply inclined surfaces of calcareous rocks in sunny situations with periodical water seepage after rain, with optimum in the montane belt.

Growth form: Crustose placodiomorph

Substrata: rocks

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

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

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: very rare

Oromediterranean belt: very rare

Montane belt: very rare

Submediterranean belt: extremely rare

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: Czeika & Czeika, Herzogia 20: 44, 2007.