Osyczka, P. 2011. The genus Cladonia, group Cocciferae, in Poland. — Herzogia 24: 231–249.
A revision of the genus Cladonia, group Cocciferae, is presented for Poland. The morphology, habitat and distribution of the taxa are treated, and the chemical races of each species and their frequency in the country have been indicated. The study is based on the examination of approximately 3300 herbarium specimens originating from Poland. Seventeen species have been accepted; the occurrence of the two previously reported species Cladonia bacilliformis and C. cyanipes has not been confirmed. Keys for all species known in Poland are provided.