Circinaria ochracea Thüs & Nascimbene

in Nascimbene & al., J. Fungi, 9,3: 9, 2023
Distribution: C - Sar (Nascimbene & al. 2023).
Description: Thallus crustose, episubstratic, areolate, the areoles angular, flat, pale yellow-orange, 0.5-0.9 mm wide, 145-170 µm thick, separated by distinct cracks in dry thalli, without a distinct prothallus. Cortex 7-8 µm thick, with a yellowish- greenish grey pigment; algal layer 40-80 µm thick; medulla white, 60-85 µm thick, hydrophobic and with air-filled spaces in water-mounted sections. Apothecia cryptolecanorine-aspicilioid, immersed in the areoles, rounded to elongate or irregular in outline, 0.3-0.5 mm wide, with a dark disc and a barely raised margin. Exciple 45-50 µm thick; epithecium with a dark yellowish-brown pigment partly soluble in N (Caesiocinerea-green), N+ emerald green, K+ pale yellow, c. 25 µm high; hymenium colourless, (123-)200-250 µm high, without oil droplets, I+ bluish; paraphyses not moniliform; hypothecium colourless. Asci (2-)4(-6)-spored, clavate, the thin outer coat K/I+ blue, the wall and apical dome K/I-. Ascospores rarely well-developed, 1-celled, hyaline, broadly ellipsoid to subglobose, 19-22 x 14-17 µm. Pycnidia black, immersed in the Thallus. Conidia bacilliform to filiform, straight to slightly curved, 10-11 x 0.3-0.4 µm. Photobiont chlorococcoid, the cells up to 9-11 µm in diam. Spot tests: cortex K- or very faintly K+ yellow (the pigment leaking in the solution), C-, KC-, P-; medulla K-. Chemistry: no lichen substances detected.
Note: a recently-described species growing on siliceous rocks in the splash-zone of permanent and temporarily dry, sun-exposed stretches of Mediterranean streams in the montane belt, hitherto known only from Sardinia.
Growth form: Crustose
Substrata: rocks
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly sexual
Periodically submerged (e.g. in creeks)

Commonnes-rarity: (info)

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

pH of the substrata:


Solar irradiation:








Altitudinal distribution:


Predictive model

Source: Nascimbene & al. 2023
Italy, Sardinia

Source: Nascimbene & al. 2023
Italy, Sardinia
Holotype of Circinaria ochracea, SMNS-STU-F0002797 (STU). (A) Section of an apothecium.(B) Globose ascospores. Scale bar =2 0 μm. (C) Pycnospores. Scale bar = 10 μm