Lecanora praepostera Nyl.

Flora, 56: 19, 1873.
Synonyms: Lecanora briquetii Zschacke; Lecanora gangaleoides f. schistina Nyl.; Lecanora sardoa Bagl.?; Lecanora schistina (Nyl.) Arnold
Distribution: C - Tosc, Laz, Sar (Monte 1993, Nöske 2000, Rizzi & al. 2011). S - Cal (Puntillo 1996).
Description: Thallus crustose, episubstratic, rimose-areolate, 3-10 cm across, white to yellowish white, often delimited by a zoned prothallus with white and blue lines. Areoles flat to usually convex, often clustered. Apothecia lecanorine, usually numerous, at first adnate then sessile and constricted at base, 0.5-1.8 mm across, with a flat to slightly convex, brown to black (often piebald), epruinose or faintly grey-pruinose disc, and a persistent, at first smooth then often wavy or crenulate thalline margin. Epithecium green to olivaceous green, often inspersed with granules, K+ red (needle-like crystals); hymenium colourless, 65-95 μm high; paraphyses simple to sparingly branched and anastomosing, 1.5-2 μm thick at base, the apical cells slightly swollen, 2-3 μm wide; hypothecium colourless. Asci 8-spored, clavate, very thin-walled, with a K/I+ blue, tall tholus penetrated by a faintly amyloid apical cushion, the wall K/I-, surrounded by a blue outer layer, Lecanora-type. Ascospores 1-celled, hyaline, ellipsoid, (8-)11-15 x 6-8 µm. Photobiont chlorococcoid. Spot tests: thallus K+ yellow turning deep red, C-, KC-, P+ yellow to red-orange, UV-. Chemistry: atranorin, norstictic acid.
Note: on steeply inclined to vertical surfaces of hard siliceous rocks, often with species of Pertusaria; mainly Tyrrhenian, and locally common in Italy at relatively low elevations.
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)

Commonnes-rarity: (info)

Alpine belt: absent
Subalpine belt: absent
Oromediterranean belt: absent
Montane belt: extremely rare
Submediterranean belt: absent
Padanian area: absent
Humid submediterranean belt: rather rare
Humid mediterranean belt: very rare
Dry mediterranean belt: absent

pH of the substrata:


Solar irradiation:








Altitudinal distribution:


Predictive model
Herbarium samples

P.L. Nimis CC BY-SA 4.0
TSB 7304

P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (9558)

Domenico Puntillo; Owner: Domenico Puntillo