ITALIC 8.0

Placidium michelii A. Massal.

Sched. Crit., 5: 100, 1856.

Synonyms: Catapyrenium michelii (A. Massal.) R. Sant.; Dermatocarpon michelii (A. Massal.) Zwackh; Endocarpon michelii (A. Massal.) Bausch; Endopyrenium michelii (A. Massal.) Körb.

Distribution: N - Ven (Lazzarin 2000b), Lomb, Piem (Isocrono & al. 2004), Emil (Fariselli & al. 2020). C - Tosc.

Description: Thallus squamulose, the squamules closely adpressed to the substratum, 1-5 mm broad, up to 0.25 µm thick, rounded to undulate, flattened, smooth, scattered to contiguous. Upper surface pale to dark chestnut brown, matt; lower surface black, attached by a dense mat of 4-6 µm thick, colourless rhizohyphae. Upper cortex paraplectenchymatous, 20-65 µm thick, without or with a very thin epinecral layer; medulla of globular cells intermixed with a few elongated cells; lower cortex thin, poorly differentiated, consisting of 1-3 layers of cells, the lower ones pigmented. Perithecia laminal, pyriform, immersed in the squamules, up to 0.35 mm across, without involucrellum. Exciple rather thin (to 25 µm), initially colourless, but soon turning dark brown throughout, starting from the ostiole; paraphyses absent, substituted by periphyses measuring 30-40 x c. 2.5 μm. Asci 8-spored, cylindrical, thin-walled, non-amyloid and without an ocular chamber, 60-70 x 10-12 μm. Ascospores 1-celled, hyaline, ellipsoid, thin-walled, 11-15 x 5-6 µm, uniseriately arranged in the asci. Pycnidia rare, multilocular, Dermatocarpon-type, laminal, immersed, black. Conidia oblong-ellipsoid, 2.5-3.5(-4) x 1.2-1.5 µm. Photobiont chlorococcoid (Myrmecia). Spot tests: cortex and medulla K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.

Note: a mainly temperate lichen found on mineral, especially sandy soil in open grasslands. Earlier dubious records from Southern Italy, and that from Latium (see Nimis 1993: 200) are not accepted here.

Growth form: Squamulose

Substrata: soil, terricolous mosses, and plant debris

Photobiont: green algae other than Trentepohlia

Reproductive strategy: mainly sexual

Commonnes-rarity: (info)

Alpine belt: absent

Subalpine belt: absent

Oromediterranean belt: absent

Montane belt: rare

Submediterranean belt: very 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

Jason Hollinger – CC BY-NC – Source: https://lichenportal.org/cnalh/collections/individual/index.php?occid=48363

USA