Cladonia diversa [Cladoniaceae, lichenized Ascomycota] - overlooked lichen in Poland

This is the first report on Cladonia diversa Asperges in Poland. Till the present this species was overlooked and usually included under the name C. coccifera. The study is based on revision of over a thousand of specimens of the genus Cladonia section Cocciferae deposited in Polish herbaria. The morphology, chemistry, habitat requirements and known distribution of the lichen in Poland are discussed. A taxonomical remarks concerning the species are also provided.