Marine fungi of Hawaii including the new genus Helicascus

Among 27 species of marine fungi recovered from natural substrata by the direct collecting procedure, found on the Hawaiian Islands Hawaii, Kauai, Maui, and Oahu (19 Ascomycetes and 8 Deuteromycetes), 22 were new locality and 12 were new Pacific Ocean records. Eight species and Helicascus kanaloanus Kohlm. gen. et sp. nov. (Pleosporaceae?) and Robillarda rhizophorae Kohlm. sp. nov. (Sphaeropsidaceae) occurred on roots of Rhizophora mangle L. Substrates not considered before in marine mycology were submerged branches and roots of Hibiscus tiliaceus L. (seven fungal species) and Pluchea × fosbergii Cooper-rider et Galang (four species). Algae contained three fungi, and foam collections four arenicolous species. Hyphomycetes known from freshwater foam in Hawaii were not found in foam along the seashore. Collections of driftwood and pilings contained 14 species. The origin of the Hawaiian marine fungal flora is discussed. Host-specific Keissleriella blepharospora and Cytospora sp. appear to have been introduced from Florida to Hawaii with seedlings of Rhizophora in 1902. Conidia of R. rhizophorae were able to germinate after freezing at −20 C for 6 months and after repeated thawing and refreezing. Half of the species collected were isolated and growth in pure culture is described. Periconia prolifica Anast. was determined as the imperfect state of Remispora cucullata Kohlm. by use of single ascospore isolations.