New additions to Omphalotaceae (Agaricales, Basidiomycota): two new rhizomorph-forming species from China

Two new rhizomorph-forming species within the family Omphalotaceae, Gymnopus fuscostipes sp. nov. and Pseudomarasmius brunneodiscus sp. nov., are proposed based on morpho-molecular evidence. Both species are characterized by marasmioid basidiomata, brownish pileus, and black rhizomorphs. Detailed morphological descriptions, color photos, and illustrations are presented herein, as well as comparisons with closely related species.