Hymenoscyphus subcarneus, a little known bryicolous discomycete found in the Białowieża National Park

Abstract

he discomycete Hymenoscyphus subcarneus was found to grow parasitic on the liverwort Cephalozia catenulata in the Białowieża National Park (Poland), and is described and illustrated from the fresh collection. Two characters, the ascus apical ring structure of the Calycina type and the contents of the living paraphyses (multiguttulate by low-refractive vacuolar bodies), have not been reported previously. In addition, a dried collection on Pohlia gracilis from Switzerland, Grimsel area, was studied. The relationship, taxonomy and infraspecific variation of the fungus are discussed. A new genus, Roseodiscus, is established to accomodate this bryicolous fungus together with two very similar equiseticolous species, Hymenoscyphus rhodoleucus and H. equisetinus. The three species are macroscopically characterized in the fresh state by a pale rosaceous-lilaceous hymenium and a mostly slender, concolorous or whitish stipe. Roseodiscus resembles Hymenoscyphus in various respects, but sharply deviates in the apical ring type which appears to indicate a more close relationship with genera like Calycina or Stamnaria. Rhizoscyphus ericae which forms a mycorrhiza with roots of Ericaceae, is compared with Roseodiscus. Based on vital observations of R. ericae this species is believed to be congeneric with the type of Pezoloma, P. griseum.