Description: Thallus foliose, broad-lobed, forming 7-15 cm wide, orbicular to irregular rosettes. Lobes (3-)5-15 mm wide, up to 30 mm long, rounded, contiguous in marginal parts, imbricate in central parts, becoming undulate, often partly scabrid-areolate, the tips ascending and sometimes shortly and thinly hairy, bright green when wet, grey to olive-green when dry. Soralia abundant, almost exclusively marginal and linear, bright yellow, with granular soredia. Lower surface thinly tomentose, pale towards margins, darker in central parts, with bright yellow, 0.1-0.6 mm wide pseudocyphellae that often reach the margins. Upper cortex of anticlinally oriented, thick-walled hyphae; medulla bright yellow throughout. Apothecia extremely rare, submarginal, glabrous, with an epruinose disc. Asci 8-spored, Peltigera-type. Ascospores 3-septate, brown, 25-30 x 6-8 μm. Photobiont chlorococcoid (Dictyochloropsis). Spot tests: cortex and medulla K-, C-, KC-, P-; medulla UV+ orange or salmon-pink. Chemistry: calycin, pulvinic acid, pulvinic dilactone, fernene triterpenoids.
Note: an oceanic-subtropical species of moist, warm, open forests, most probably extinct in Italy. The most recent record dates back to 1923 (Marche), with a record by Jatta from Abruzzo (Nimis 1993: 579): both records, from the eastern side of the Peninsula, being dubious are not accepted here. However, the species was also reported from warm-humid areas of southern Italy (Gargano-Puglia and Sicilia) by Flotow and Rabenhorst (Nimis 1993: 579). In southern Italy there are warm-humid sites which could have hosted this species.
Growth form: Foliose, broad lobed
Photobiont: green algae other than Trentepohlia
Reproductive strategy: mainly asexual, by soredia, or soredia-like structures (e.g. blastidia)