The forgotten Calonectria collection: Pouring old wine into new bags.

The genus Calonectria with its Cylindrocladium asexual morphs has been subject to several taxonomic revisions in the past. These have resulted in the recognition of 116 species, of which all but two species (C. hederae and C. pyrochroa) are supported by ex-type cultures and supplemented with DNA barcodes. The present study is based on a large collection of unidentified Calonectria isolates that have been collected over a period of 20 years from various substrates worldwide, which has remained unstudied in the basement of the CBS-KNAW Fungal Biodiversity Centre. Employing a polyphasic approach, the identities of these isolates were resolved and shown to represent many new phylogenetic species. Of these, 24 are newly described, while C. uniseptata is reinstated at species level. We now recognise 141 species that include some of the most important plant pathogens globally.