ITALIC 8.0

Verrucaria devensis (G. Salisb.) Orange

Lichenologist, 46: 607, 2014. Basionym: Leucocarpopsis devensis G. Salisb. - Nova Hedwigia, 26: 351, 1975

Synonyms:

Distribution: C - Sar (Nascimbene & al. 2023).

Description: Thallus crustose, episubstratic, pale grey, dull grey-green to greenish grey, mid-grey-brown or mid-brown, smooth, weakly subgelatinous but never transparent when wet, continuous or cracked in central parts, the cracks at least partially delimiting 40-600 µm wide secondary areoles containing 1-7 perithecia, the surface of areoles typically slightly convex or uneven; prothallus whitish, not fimbriate. Thallus 40-70 µm thick away from perithecia, up to 140 µm thick near perithecia, the cells irregularly arranged or in weak vertical columns, air spaces between cells absent or very few; pseudocortex cells with a dilute or moderately dense brown pigment in the walls; epinecral layer absent or thin, usually indistinct, up to 10 µm thick; dark basal layer present either locally or extensively. Perithecia black, immersed, forming very low projections, the apex at first visible only near the ostiole as a grey, c. 20 µm wide dot, later visible as a grey or black, up to 180 µm wide disc. Involucrellum at first conical, then very wide-spreading and confluent with other involucrella, forming the dark basal layer; surface of involucrellum densely pigmented, below paler, with pigment largely confined to cell walls. Exciple 120-210 µm across, colourless at sides and base. Hamathecium of c. 20-30 µm long periphysoids, interascal filaments absent; hymenial gel hemiamyloid, I+ red (I+ blue at very low concentrations of I), K/I+ blue. Asci 8-spored, clavate, I-, fissitunicate, the wall thickened above, with an ocular chamber, dehiscent by extrusion of an endotunica to form a delicate rostrum, Verrucaria-type. Ascospores 1-celled, hyaline, oblong- ellipsoid, (16-)18-22(-23) x (7.5-)8.5-9.5(-10.5) µm, (1.7-)2.2-2.4(-2.6) times as long as wide. Photobiont chlorococcoid, the cells irregularly arranged or in weakly defined vertical columns. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.

Note: on more or less shaded and humid surfaces of siliceous rocks, frequently to occasionally submerged in temporarily inundated sites along streams and creeks; described from the British Isles, hitherto reported only from Sardinia. The species is easily confused with V. praetermissa, which has a less strongly pigmented, slightly thicker, less uneven, not subgelatinous thallus; when the two species grow together, the differences are easily seen, even in the field; however, both are variable in appearance so that some individual specimens may be difficult to name without DNA analysis. For further details see Orange & al. (2023).

Growth form: Crustose

Substrata: rocks

Photobiont: green algae other than Trentepohlia

Reproductive strategy: mainly sexual

Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)

Periodically submerged (e.g. in creeks)

Commonnes-rarity: (info)

Alpine belt: absent

Subalpine belt: absent

Oromediterranean belt: absent

Montane belt: absent

Submediterranean belt: absent

Padanian area: absent

Humid submediterranean belt: extremely rare

Humid mediterranean belt: extremely rare

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

INDEX FUNGORUM GBIF

Source: Nascimbene & al. 2023

Italy, Sardinia
Specimen of Verrucaria devensis from Sardinia with smooth and almost uncracked thallus, SMNS-STU-F0002806. Scale bar = 0.5 mm.