ABSTRACTThe significance of hydrocarbonoclastic filamentous fungi in marine environments is unclear, only poorly adapted terrigenous species having been investigated. This report examines 54 strains indigenous to submerged wood, saltmarsh vegetation and sandy beaches. Beach-adaptedCorollospora, Dendryphiella, LulworthiaandVaricosporinaspecies grew using alkanes and alkenes as sole carbon sources and mineralized n[1-14C]hexadecane. This ability was unrelated to oil pollution at fungal collection sites. Few fungi from other habitats utilized hydrocarbons. The beach fungi have been well positioned for selection of hydrocarbon utilization, interfacing with natural marine hydrocarbons in lipophilic surface films and sea foam, long before anthropogenic petroleum compounds polluted their environment.