Language: French, with bilingual abstract in English and French
Determination keys, original descriptions based on Luxembourg material, notes on the distribution and ecology and a list of the Luxembourg references are given for 184 taxa of epiphytic crustose lichens and 58 species of fungi growing on epiphytic lichens found in Luxembourg. The new combination Lecidella conspurcatosorediosa (Harm.) Diederich comb. nov. is introduced for a sorediate species growing exclusively on barks rich in ferruginous dust; the combination Biatora epixanthoides (Nyl.) Diederich comb. nov. is proposed for the species often called Bacidia epixanthoides. The Luxembourg specimens provisionally called Halecania viridescens represent perhaps a different undescribed Halecania species