• Species: Arthothelium spectabile Flot. ex A. Massal.
• Remark:
• Fungus type: lichenized
• Treatment in Estonia: certain

• Species: Arthrorhaphis aeruginosa R. Sant. & Tønsberg
• Remark:
• Fungus type: lichenicolous
• Treatment in Estonia: certain

• Species: Arthrorhaphis citrinella (Ach.) Poelt
• Remark:
• Fungus type: lichenized
• Treatment in Estonia: certain

• Species: Arthrosporum populorum A. Massal.
• Remark: see: Toninia populorum (A. Massal.) Kistenich, Timdal, Bendiksby & S. Ekman
• Fungus type: lichenized
• Treatment in Estonia: synonym

• Species: Aspicilia caesiocinerea (Nyl. ex Malbr.) Arnold
• Remark: see: Circinaria caesiocinerea
• Fungus type: lichenized
• Treatment in Estonia: synonym

• Species: Aspicilia calcarea (L.) Mudd
• Remark: see: Circinaria calcarea
• Fungus type: lichenized
• Treatment in Estonia: synonym
• lubi-lehtersamblik

• Species: Aspicilia cinerea (L.) Körb.
• Remark: includes earlier misidentifications of Aspicilia simoënsis Räsänen and Bellemerea alpina (Sommerf.) Clauzade & Cl. Roux
• Fungus type: lichenized
• Treatment in Estonia: certain
• hall lehtersamblik

• Species: Aspicilia contorta (Hoffm.) Kremp. ssp. contorta
• Remark: see: Circinaria contorta
• Fungus type: lichenized
• Treatment in Estonia: synonym

• Species: Aspicilia contorta ssp. hoffmanniana S. Ekman & Fröberg
• Remark: see: Circinaria hoffmanniana
• Fungus type: lichenized
• Treatment in Estonia: synonym

• Species: Aspicilia gibbosa (Ach.) Körb.
• Remark: see: Circinaria gibbosa
• Fungus type: lichenized
• Treatment in Estonia: synonym extinct

• Species:
• Remark:
• Fungus type:
• Treatment in Estonia: