Taxonomy of Orphnodactylis kalmiae gen. et sp.nov. influenced by the hyperparasite Didymosphaeria kalmiae

Abstract

The holotype of Dothidea kalmiae Peck, putitive cause of the twig blight disease of Kalmia angustifolia (Ericaceae) in North America, was examined and found to contain two species of ascomycetes. The original diagnosis of D. kalmiae included elements of both fungi. Additional material from other parts of North America were also examined and found to contain these two fungi. The two ascomycetes are determined to be (1) a member of the Phyllachoracecae characterized by black stromata and parasitic on Kalmia spp., and (2) a member of the genus Didymosphaeria parasitic in the ascomata of the first species. For reasons of nomenclatural stability and the availability of useful holotypes, Dothidea kalmiae is chosen to represent the hyperparasite and transferred to Didymosphaeria as Didymosphaeria kalmiae (Peck) Malloch and Mallik comb.nov. The species causing the twig blight is described as the type of the new genus and species Orphnodactylis kalmiae. Phyllachora wittrockii, the agent of a similar disease of Linnaea borealis (Caprifoliaceae), is transferred to Orphnodactylis as Orphnodactylis wittrockii (Erikss.) Malloch and Mallik. Two coelomycetes, members of the genera Diplodina and Phoma recorded in stromata of O. kalmiae by previous workers are described and illustrated. The life history of O. kalmiae is discussed briefly.Key words: Kalmia, sheep laurel, Didymosphaeria, Orphnodactylis, Phyllachora, hyperparasitism.