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

Abstract

he discomycete <em>Hymenoscyphus subcarneus</em> was found to grow parasitic on the liverwort <em>Cephalozia catenulata</em> in the Białowieża National Park (Poland), and is described and illustrated from the fresh collection. Two characters, the ascus apical ring structure of the <em>Calycina</em> 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 <em>Pohlia gracilis</em> from Switzerland, Grimsel area, was studied. The relationship, taxonomy and infraspecific variation of the fungus are discussed. A new genus, <em>Roseodiscus</em>, is established to accomodate this bryicolous fungus together with two very similar equiseticolous species, <em>Hymenoscyphus rhodoleucus</em> and <em>H. equisetinus</em>. The three species are macroscopically characterized in the fresh state by a pale rosaceous-lilaceous hymenium and a mostly slender, concolorous or whitish stipe.<em> Roseodiscus</em> resembles <em>Hymenoscyphus</em> in various respects, but sharply deviates in the apical ring type which appears to indicate a more close relationship with genera like <em>Calycina</em> or <em>Stamnaria</em>. <em>Rhizoscyphus ericae</em> which forms a mycorrhiza with roots of Ericaceae, is compared with <em>Roseodiscus</em>. Based on vital observations of <em>R. ericae</em> this species is believed to be congeneric with the type of <em>Pezoloma, P. griseum</em>.