Hypotrachyna afrorevoluta (Krog & Swinscow) Krog & Swinscow

    Thallus foliose, more or less adnate, orbicular, to 10 cm across (on rocks), lobes 1-6 mm wide, short, lobe apices widened, rounded to crenulate divided by sinuous axils, turned down at the tips, upper surface cortex delicate, easily cracked, white-grey, pale grey-bluish, pale grey-green, covered with marginal pustulate soralia leaving black scars when falling, and white to pale greenish granular soredia (never dark), lower surface glossy, brown-black with bright rhizines, black, rather long, simple or branched. Apothecia rare, semi-stalked, 0.5-0.8 cm diam., exciple crenulate/sorediate. Ascospores simple, ellipsoid, 11-19 x 6-12 µm. Photobiont: trebouxioid. Cortex : K+ yellow ; medullae : C+ pink, K-, KC+ dark pink, Pd-. Strong oceanic and thermophile trends, mainly on bark but common on rocks near the seashore in our prospection area, see : Hypotrachyna afrorevoluta forme saxicole, rare on wood, see : Hypotrachyna afrorevoluta forme lignicole, sometimes, but rarely, on artificial substrates (plastic boat hulls), see: Hypotrachyna afrorevoluta forme sur substrats artificiels. 

N.B. See Hypotrachyna britannica that grows exclusively on rocks in the coastal zone has dark blue-black soredia; some authors consider that this species is only a morph of Hypotrachyna afrorevoluta adapted to well-lit habitats.

_ See also Hypotrachyna revoluta of which the soralia structure is less canonical, pale greenish and mainly marginal, the brown lobes lower surface has short rhizines, forked or branched.