Lepra leucosora (Nyl.) Hafellner
=Pertusaria leucosora Nyl.
Pertusaria leucosora Nyl.
Pertusaria digrediens (Nyl.) Zahlbr.
Thallus crustose, usually rather circular, to 10 cm diam., rather thick, areolate, greyish, pale to dark grey, surface uneven with warts, 0.5-1.5 mm diam., soralia abundant, rounded, clustered towards the center, whitish, soredia indistinctly granulose, whitish, margin with a zonate structure but without visible prothallus. Apothecia unknown. Thallus, cortex and medulla: C-, K-, KC+/-yellowish to yellow-reddish, Pd +/- yellow > orange to orange-reddish (notably soralia). On alkaline rocks near the seashore: basalts, serpentine, but also on weakly acid rocks inland (schist ridges). N.B. May be very close to (or even synonym according to some authors) Lepra aspergilla but different by its chemical reactions ( more orange) and the rounded soralia. N.B. This species is higly variable, notably considering its chemical properties, and subjected to various interpretations. It probably encompasses several taxa; to British authors, limited to the English Channel islands and to Cornwall coastal regions see Lepra leucosora ss. auct. brit.; French authors however tends towards considering it is a ubiquist species... Additional investigations are needed to clarify this specific point.