ITALIC 8.0

Xanthoparmelia mexicana (Gyeln.) Hale

Phytologia, 28: 488, 1974. Basionym: Parmelia mexicana Gyeln. - Feddes Rep., 29: 488, 1931.

Synonyms:

Distribution: N - Lomb (Favero-Longo & al. 2023), Lig (Giordani & al. 2009). C - Sar (Nöske 2000, Giordani & al. 2002b, Rizzi & al. 2011).

Description: Thallus foliose, heteromerous, dorsiventral, rather tightly adnate, forming orbicular to irregular, 4-10 cm wide rosettes. Lobes elongate, flat to slightly convex, separate to somewhat imbricate, (0.5-)1.5-4 mm wide, the upper surface greenish yellow, shiny, smooth, emaculate, with at first subglobose, but soon cylindrical-coralloid, 0.1-0.2 mm thick, 0.1-0.5 mm tall isidia with dark tips. Lower surface pale brown, with simple, concolorous, 0.2-0.5 mm long rhizines. Upper cortex paraplectenchymatous, with a pored epicortex, the cell walls with Xanthoparmelia-type lichenan; medulla white; lower cortex paraplectenchymatous. Apothecia rare, lecanorine, substipitate, 2-7 mm across, with a brown disc and an often isidiate thalline margin. Epithecium brown; hymenium and hypothecium colourless; paraphyses simple; hypothecium colourless. Asci 8-spored, clavate, the K/I+ blue tholus penetrated by a faintly amyloid apical cushion with parallel or diverging flanks, the wall K/I-, surrounded by a K/I+ blue outer layer, Lecanora-type. Ascospores 1-celled, hyaline, ellipsoid, 9-10 x 4-5 µm. Pycnidia rare, black, immersed. Conidia bifusiform, 6-7 x 1 µm. Photobiont chlorococcoid. Spot tests: upper cortex K-, C-, KC- or KC+ yellow, P-; medulla K+ yellow turning dark red, C-, KC-, P+ orange. Chemistry: upper cortex with usnic acid; medulla with salazinic acid (major) consalazinic acid (minor), and usually norstictic and protocetraric acids (trace).

Note: on siliceous rocks wetted by rain, perhaps more widespread in Mediterranean Italy and in the dry Alpine valleys. Molecular data indicate that American and European samples, although morphologically and chemically similar, are only distantly related (Barcenas-Peña & al. 2018).

Growth form: Foliose, broad lobed

Substrata: rocks

Photobiont: green algae other than Trentepohlia

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

Commonnes-rarity: (info)

Alpine belt: absent

Subalpine belt: absent

Oromediterranean belt: absent

Montane belt: absent

Submediterranean belt: absent

Padanian area: absent

Humid submediterranean belt: very rare

Humid mediterranean belt: very rare

Dry mediterranean belt: rare

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

Index Fungorum GBIF

P.L. Nimis CC BY-SA 04

GE

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

Herbarium: GE
2002/02/13
isidia, specimen from Sardinia

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

Herbarium: GE
2002/02/13
lower surface, specimen from Sardinia, det. J. Elix

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

Herbarium: GE
2002/02/13
specimen from Sardinia, det. J. Elix