The crustose lichen genus Mycoblastus in the Northern Hemisphere includes eight recognized species sharing large, simple ascospores produced 1–2 per ascus in strongly pigmented biatorine apothecia. The monophyly of Mycoblastus and the relationship of its various species to Tephromelataceae have never been studied in detail. Data from ITS rDNA and the genes coding for translation elongation factor 1-α and DNA replication licensing factor mini-chromosome maintenance complex 7 support the distinctness of Mycoblastus s. str. from the core of the Tephromelataceae, but recover M. fucatus and an undescribed Asian species as strongly supported within the latter group. We propose accommodating these two species in a new genus, Violella, which is characterized by its brownish inner ascospore walls, Fucatus-violet hymenial pigment granules and secondary chemistry, and discuss the position of Violella relative to Calvitimela and Tephromela. We describe the new species Violella wangii T. Sprib. & Goffinet to accommodate a new species with roccellic acid from Bhutan, China, India and the Russian Far East. We also exclude Mycoblastus indicus Awasthi & Agarwal from the genus Mycoblastus and propose for it the new combination Malmidea indica (Awasthi & Agarwal) Hafellner & T. Sprib.
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