Scytinium magnussonii  

Thallus foliose, to 5 cm broad. Lobes rounded, irregular, 2-3 mm wide (to only 1.2 mm in GB material); upper surface smooth, partially finely striate with isidia, dark blue-grey, often brownish, margins undulate with clusters of granulate or coralloid aggregated isidia,  usually brown apically. Lower surface similar to upper, but paler, without rhizines or tomentum. Anatomy: thallus heteromerous, 100-125 µm thick; upper and lower cortex dark-coloured, paraplectenchymatous, 10-12 µm thick, small-celled, individual cells 4.5-6.5 µm diam; inner part of unorientated, interwoven hyphae with aggregates of Nostoc cells, individual cells 4-6 µm diam.

Anamorph: not known.

Teleomorph: ascomata apothecia, very rare, known only in an immature state (0.5 mm diam), laminal, shortly pedicellate with distinct pale thalline, often isidiate margin; disc concave, brownish. Thalline margin 25-40 µm thick, proper exciple composed of small thin-walled cells with isodiametric lumina, 20-50 µm thick. Subhymenium I+ blue, to 40 µm thick, of closely compacted, unorientated hyphae. Hymenium 130-150 µm high, I+ blue, paraphyses conglutinated in a gelatinous matrix, ca 2 µm diam, enlarged apically to ca 4.5 µm with external brown pigmentation. Asci clavate, not fully developed, without ripe spores.