THE NOMENCLATURE OF THE BEECH BARK FUNGUS: A SOLUTION TO THE COMPLEX CASE OF ASCODICHAENA, DICHAENA AND POLYMORPHUM

Abstract

SummaryThe nomenclature of the common north‐temperate beech bark fungus, which also occurs on oak twigs, is reviewed. It has a pleomorphic life cycle and changes in the Code effected at the Sydney Congress in Arts. 10, 13 and 59 affect its nomenclature. It is concluded that the correct generic name for the teleomorph is Ascodichaena Butin, and that for the anamorph is Polymorphum Chev. (syn. Dichaena Fr.). The correct species name for the teleomorph is Ascodichaena rugosa Butin (syn. Lichen rugosus L.), while the name Polymorphum quercinum (Pers.) Chev. is to be applied to the anamorph. All generic and specific epithets are reviewed and revised synonymies presented. In the course of this study it was discovered that the name Opegrapha vulgata (Ach.) Ach. was illegitimate and must be referred to A. rugosa; the correct name for this common lichen was not investigated. The name Dichaenopsis notarisii Paoli was based on stremata of A. rugosa invaded by the Stagonospora‐like anamorph of Keissleriella bavarica Butin.