Utilising bryophyte herbarium material as a source of fungal novelty: a case study presenting new records of Bryobroma gymnomitrii (Döbbeler) Döbbeler on Gymnomitrion Corda in Britain and North America

Introduction Bryophyte herbarium material often contains inadvertently collected bryophilous fungi preserved with their host plant tissues, providing snapshots of the biotic aspects of bryophyte ecology in space and time. During an ongoing project to study bryophilous fungi on leafy liverworts in the genus Gymnomitrion, new records of the bryophilous ascomycete Bryobroma gymnomitrii (≡ Bryomyces gymnomitrii) were discovered in herbarium material from areas in which the fungus was previously unknown. While many host vouchers were screened, the fungus was observed in only five collections. Using B. gymnomitrii as a case study, some of the advantages and limitations associated with the utility of bryophyte collections for bryo-mycological analyses are considered.