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 fertile very rare, on trees at the water's edge.

_ Hypotrachyna afrorevoluta forme corticole, which comes on the bark of trees.   

_ Hypotrachyna afrorevoluta forme saxicole, which comes on rocks especially in forests.

_ Hypotrachyna afrorevoluta forme lignicole which comes on worked or dead wood. 

_ Hypotrachyna afrorevoluta forme sur substrats artificiels, which comes on artificial substrates (plastic boat hulls, etc.).

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.

N.B. The current name afrorevoluta is inappropriate and will need to be changed, as the European material identified as Hypotrachyna afrorevoluta occupies a different clade from the tropical collections. A complete revision of the species complex is therefore necessary.