Hypotrachyna afrorevoluta (Krog & Swinscow) Krog & Swinscow
Lichenologist, 19: 420, 1987. Basionym: Parmelia afrorevoluta Krog & Swinscow - Norw. J. Bot., 26: 22, 1979.
Synonyms: Parmelinopsis afrorevoluta (Krog & Swinscow) Elix & Hale
Distribution: N - TAA (Nascimbene & al. 2021), Lig (UPS- L-187671). C - Umb (Brackel 2015), Laz (Brackel 2015).
Description: Thallus foliose, heteromerous, dorsiventral, rather loosely attached, forming up to 4-6(-10) cm wide patches. Lobes 2-5(-6) mm wide, 0.5-1.5 cm long, rounded at apex, crenulate, with sinuous, rounded axils, down-turned tips, and an easily cracked, white-grey, blue-grey or pale grey-green, emaculate, more or less shiny upper surface covered with submarginal to laminal, pustulate soralia deriving from the break-up of upper cortex, the soredia white to pale greenish, rarely turning blackish, coarsely granular. Lower surface black, rarely dark brown in marginal parts, that of young lobes shiny, with shiny, long, black, simple to irregularly branched rhizines, some of which usually project beyond lobe margins. Upper cortex of tightly packed, anticlinally oriented hyphae, with a pored epicortex, the cell walls with isolichenan; medulla white, but appearing blackish when exposed in eroded soralia; lower cortex brown, of anticlinally oriented hyphae. Apothecia rather rare, lecanorine, up to 6(-10) mm across, strongly constricted at base, with a brown disc and a crenulate, sorediate thalline margin. Epithecium brown; hymenium and hypothecium colourless. Asci 8-spored, clavate, Lecanora-type. Ascospores 1-celled, hyaline, ellipsoid to broadly ellipsoid, 11-19 x 6-12 μm. Pycnidia rare, immersed, laminal. Conidia bifusiform. Photobiont chlorococcoid. Spot tests: upper cortex K+ yellow C-, KC- P-; medulla K-, C+ pink, KC+ pink-red, P-, UV-. Chemistry: upper cortex with atranorin and chloratranorin; medulla with gyrophoric acid (major), lecanoric acid (minor), and related accessory substances (hiascic, 4, 5-di-O-methylhiascic, 5-O-methylhiascic acids).
Note: a species differing from H. revoluta by lobes with a glossy lower surface, often simple, glossy rhizines, and coarse soredia developing from pustules, based on a type from Eastern Africa. It grows on bark of broad-leaved trees in areas with a more or less oceanic climate; widely distributed on both Hemispheres, and perhaps spreading in Europe in recent years. The species is very similar to H. revoluta, and several Italian records of the latter could refer to it. See also note on H. revoluta.
Growth form: Foliose, broad lobed
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)
Most common in areas with a humid-warm climate (e.g. most of Tyrrenian Italy)