Circinaria nimisii Sohrabi, H. Mayrhofer, Obermayer & S. D. Leav.

Lichenologist, 55: 368, 2023
Synonyms: Aspicilia desertorum auct. p.p. non (Kremp.) Mereschk.; Aspicilia esculenta auct. p.p. non (Pall.) Flagey
Distribution: C - Abr (Nimis & Tretiach 1999; Ravera & al. 2024a).
Description: Thallus at first crustose, of bullate to subcylindrical areoles, then becoming subfruticose and vagrant, consisting of tiny branches or flattened lobes, forming pebble-like, 0.5-2 cm tall and 0.5-2 (-3) cm wide, usually spherical to irregular, rarely flattened, often coralloid clumps; lobes dense, often forming a distinct, erected, areole-like surface, attached to the central portion of the thallus, very compact, short to relatively elongate; main lobes radiating from the central axial part, usually wider, up to 1.5-5 mm diam., more or less rimose in uppermost parts, somewhat flattened on top, up to 0.2-0.6 cm in the oldest parts. Exposed side usually dull brown, brownish grey to greyish green, sometimes whitish grey, pale olive-brown or pale brown; surface of the covered side usually dark green to dark brown, greenish brown. Branch tips not tapering, obtuse, pulvinate, not blackened. Pseudocyphellae very common, white, formed along the branches and visible at their tops. Cortex one-layered, (15-)20-40(-65) μm thick, paraplectenchymatous, more or less brown, c. 2-3 cells thick, the cells (4-)6-10(-12) μm in diam.; inner part indistinct, mixed with prosoplectenchymatous tissue of medulla; medulla white to often muddy, 0.3-10 mm thick, I-, containing calcium oxalate crystals. Apothecia aspicilioid, round to somewhat irregular, at first immersed and appearing as white-pruinose orbicular dots, then sessile to substipitate, up to 0.5.1.5(-3) mm across, with a black to brown-black, often thinly white-pruinose disc and a more or less raised, (prominent in older apothecia), entire thalline margin. Proper exciple (25-)35-85(-95) μm wide, the uppermost cells brown, subglobose, 4-5(-7) μm in diam.; epithecium K+ brown to light yellowish green, N+ pale green; hymenium colourless, occasionally with a few oil drops, (100-)110-140(-150) μm high, I+ blue; paraphyses branched, moniliform to submoniliform, the upper cells subglobose, 4-7 μm wide, the lower cells 5-9 x 2-3 μm wide; hypothecium pale, (35-)45-65(-85) μm high, I+ blue. Asci 2-4(-5)-spored, broadly clavate, with a 20-30 μm thick apical dome, (80-)90-100(-110) x 25-35 μm. Ascospores 1-celled, hyaline, globose to subglobose, (13-)15-20(-23) x (12-)14-20(-22) μm. Pycnidia immersed, single, flask-shaped, the wall colourless in lower part, black to brownish near the ostiole. Conidia filiform, straight to very slightly curved, (8-)10-14(-17) x 1-1.3 μm. Photobiont chlorococcoid, the cells clustered in small groups, especially in the thalline margin of apothecia. Spot tests: cortex and medulla K-, C-, KC-, P-, UV-. Chemistry: without lichen substances.
Note: this species was recently described from Mt. Olympus (Greece) as a vagrant lichen in steppe-like vegetation over calcareous substrata. Specimens collected on rock in the Gran Sasso Massif (Central Apennines), identified by Nimis & Tretiach (1999) as Aspicilia desertorum and provisionally assigned to Circinaria elmorei by Nimis (2016), proved to correspond fairly well with the description of C. nimisii (in prep.), with the only difference that the thalli of Italian specimens, although easily detachable, were not truly vagrant.
Growth form: Fruticose

Substrata: rocks, soil, terricolous mosses, and plant debris
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
Subcontinental: restricted to areas with a dry-subcontinental climate (e.g. dry Alpine valleys, parts of Mediterranean Italy)

Commonnes-rarity: (info)

Alpine belt: extremely rare
Subalpine belt: absent
Oromediterranean belt: extremely rare
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


P.L. Nimis CC BY-SA 4.0
TSB 13559



Pier Luigi Nimis - CC BY-SA 4.0
TSB 13559



Pier Luigi Nimis - CC BY-SA 4.0
TSB 13559



P.L. Nimis; Owner: Department of Life Sciences, University of Trieste
Herbarium: TSB (13559)
2001/11/22


Source: Sohrabi M, Leavitt SD, Obermayer W, Mayrhofer H. Circinaria nimisii (Megasporaceae, lichenized Ascomycota), a new manna lichen from Greece. The Lichenologist. 2023;55(5):367-376. doi:10.1017/S0024282923000336
Circinaria nimisii (H. Mayrhofer 15811: A–F holotype in GZU; G & H isotype in H). A & B, thallus (in A with apothecia). C, aspicilioid apothecia arising from the thallus. D, phenotype with abundant pseudocyphellae forming conspicuous whitish dots. E, asci (in KOH) with thickened tholus and spores (the ascus furthest to the right has burst at the base and thus the apical tholus protrudes into the ascoplast). F, conidia (in KOH). G, section through a pycnidium (stained with lactophenol cotton blue). H, section through the thallus showing the typical cortex type with a paraplectenchymatous tissue (stained with lactophenol cotton blue). E & F photographed using differential interference contrast microscopy. Scales: A & B = 2 mm; C & D = 0.5 mm; E, G & H = 20 μm; F = 10 μm.


Source: Sohrabi M, Leavitt SD, Obermayer W, Mayrhofer H. Circinaria nimisii (Megasporaceae, lichenized Ascomycota), a new manna lichen from Greece. The Lichenologist. 2023;55(5):367-376. doi:10.1017/S0024282923000336
Circinaria nimisii (H. Mayrhofer 15811: A–F holotype in GZU; G & H isotype in H). A & B, thallus (in A with apothecia). C, aspicilioid apothecia arising from the thallus. D, phenotype with abundant pseudocyphellae forming conspicuous whitish dots. E, asci (in KOH) with thickened tholus and spores (the ascus furthest to the right has burst at the base and thus the apical tholus protrudes into the ascoplast). F, conidia (in KOH). G, section through a pycnidium (stained with lactophenol cotton blue). H, section through the thallus showing the typical cortex type with a paraplectenchymatous tissue (stained with lactophenol cotton blue). E & F photographed using differential interference contrast microscopy. Scales: A & B = 2 mm; C & D = 0.5 mm; E, G & H = 20 μm; F = 10 μm.