Three new species and a new synonym of Conocybe section Ochromarasmius subsection Dumetorae (Bolbitiaceae, Agaricales) from northern China

Based on morphological observations, this study reports the first discovery of species from section Ochromarasmius in China. Using combined internal transcribed spacer (ITS), nuclear large subunit ribosomal DNA (nrLSU), and translation elongation factor 1 - alpha (tef 1 - α) sequences, Bayesian and maximum likelihood phylogenies were reconstructed for sect. Ochromarasmius.

The resulting phylogenetic trees indicate that subsect. Dumetorae forms a monophyletic group. Subsect.

Subdumetorae, in terms of both its definition and phylogenetic placement, is entirely nested within subsect. Dumetorae; therefore, it is treated as a later synonym. Furthermore, subsect.

Dumetorae encompasses three new species from northern China: Conocybe verrucosa, C. arenicola, and C. subfusispora. Thus, the total number of species in subsect. Dumetorae is increased to 11 and that in sect.

Ochromarasmius to 14. Additionally, based on morphological characteristics, putative phylogenetic positions are discussed for the other subsections and species within sect. Ochromarasmius that currently lack molecular sequence data.

The study also provides an identification key for sect. Ochromarasmius subsect. Dumetorae, accompanied by morphological descriptions and line drawings of the new species.