Valsa viburni, a rare fungus in Europe?

The paper provides brief illustrated description and general distribution of Valsa viburni. The fungus is found to be highly host-specific and confined to Viburnum lantana. According to currently available data on its distribution, the species has small number of records, fragmented range and is shown to be rare in Europe. However, before assessment of the species, information on any additional unrecorded specimens is needed. On the example of V. viburni, some issues on fungal conservation for species of microfungi are considered.