Basionym Name:Placodium exiguum Müll. Arg., Revue mycol., Toulouse 10(no. 38): 59 (1888)
Homotypic synonyms:Acarospora exigua (Müll. Arg.) Hue, Nouv. Arch. Mus. Hist. Nat., Paris, 5 sér. 1(2): 161 (1909)