Diplotomma dispersum (Kremp.) Arnold

Flora, 55: 195, 1872. Basionym: Diplotomma alboatrum var. dispersum Kremp. - Denkschr. kgl. bayer. bot. Ges., Abt. 2, 4: 209, 1861
Synonyms: Buellia subdispersa Mig.; Diplotomma subdispersum (Mig.) Etayo & Breuss
Distribution: N - Frl, Ven (Nascimbene & al. 2021), TAA (Nascimbene & al. 2021), Lomb, Piem (TSB 25801). S- Bas (Nascimbene & al. 2021).
Description: Thallus crustose, episubstratic, rather thick, chalky white, areolate, forming small (1-4 mm wide) patches, the areoles irregular in outline, flat to slightly convex, dispersed to contiguous and separated by deep cracks. Medulla white, I+ blue. Apothecia lecideine, black, 0.3-0.4(-0.6) mm across, subimmersed to subsessile, with a soon convex, usually epruinose disc, and a soon excluded proper margin. Proper exciple brown in outer part, paler within, c. 30 μm wide; epithecium brown; hymenium colourless, K/I+ blue; paraphyses simple, slightly capitate; hypothecium reddish brown. Asci 8-spored, clavate to cylindrical-clavate, the apical dome K/I+ dark blue with a pale, conical-pointed apical cushion (axial mass), the wall I-, but the thin outer gel I+ blue, approaching the Bacidia-type. Ascospores (2-)3-septate, brown, ellipsoid, slightly curved and bean-shaped, 12-19(-22) x 5-8 μm, with a minutely granulose ornamentation over the whole surface. Photobiont chlorococcoid. Spot tests: K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: an apparently widespread but rare, or at least rarely distinguished, calcicolous species, most often found on weakly to strongly calcareous rocks, often on rain-protected surfaces, mostly above treeline; it often starts the life-cycle on other crustose lichens. The species, characterised by four-celled spores with transverse septa only, and by the I+ blue reaction of the medulla, is very closely related to (and often synonymized with) the silicicolous D. lutosum, which differs in the more strongly ornamented spores and in the ecology. I have placed here all earlier records of D. lutosum from calcareous rocks in upland areas.
Growth form: Crustose
Substrata: rocks
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
paras crustose lichens when young (facultatively)

Commonnes-rarity: (info)

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

pH of the substrata:

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Solar irradiation:

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Aridity:

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Eutrophication:

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Poleotolerance:

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Altitudinal distribution:

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Predictive model
Herbarium samples
Index Fungorum GBIF


Pier Luigi Nimis - CC BY-SA 4.0
TSB 42405



Pier Luigi Nimis - CC BY-SA 4.0
TSB 42405



Juri Nascimbene - CC BY-SA 4.0
Italy, E Alps
Herb. Nascimbene



Juri Nascimbene - CC BY-SA 4.0
Italy, E Alps
Herb. Nascimbene



Juri Nascimbene - CC BY-SA 4.0
Italy, E Alps
Herb. Nascimbene



P.L. Nimis CC BY-SA 4.0
TSB 42405



P.L. Nimis CC BY-SA 4.0
TSB 8271



P.L. Nimis CC BY-SA 4.0
TSB 41223



P.L. Nimis CC BY-SA 4.0
TSB 41223



P.L. Nimis CC BY-SA 4.0
TSB 41223



P.L. Nimis CC BY-SA 4.0
TSB 41223



Pier Luigi Nimis - CC BY-SA 4.0
TSB 37976)



Pier Luigi Nimis - CC BY-SA 4.0
TSB 37976)



Pier Luigi Nimis - CC BY-SA 4.0
TSB 37976)



Pier Luigi Nimis - CC BY-SA 4.0
TSB 37872)



Pier Luigi Nimis - CC BY-SA 4.0
TSB 37873)