Taxonomic revision of Conobolbitina (Bolbitiaceae, Agaricales) based on collections from Jilin Province, China

<i>Conobolbitina</i> is a morphologically diverse transitional genus within the Bolbitiaceae. However, taxonomic confusion persists, as some of its species remain classified under other genera, and its section <i>Verrucisporae</i> has been recovered as paraphyletic. This study revises the subdivision of <i>Conobolbitina</i> using integrated morphological and phylogenetic analyses of specimens from Jilin Province, China. A combined dataset of the internal transcribed spacer (ITS), nuclear large subunit ribosomal DNA (nrLSU), and translation elongation factor 1-alpha (<i>tef</i>1-α) sequences was analyzed using maximum likelihood (ML) and Bayesian inference (BI). Phylogenetic results revealed four major monophyletic clades within <i>Conobolbitina</i>, corresponding to its four sections. In sect. <i>Conobolbitina</i>, new combinations are proposed for two species, <i>Con. sulcata</i> and <i>Con. striipes</i>. In sect. <i>Aeruginosa</i>, <i>Con. atrocyanea</i> is newly combined. For sect. <i>Verrucisporae</i>, its circumscription is revised by excluding the taxa responsible for its paraphyly, and a new combination, <i>Con. australis</i>, is proposed. To accommodate the excluded taxa from sect. <i>Verrucisporae</i>, a new section, sect. <i>Lignicola</i>, is established based on morphological and phylogenetic evidence. Within this new section, three species, <i>Con. glutinosa</i>, <i>Con. viscosa</i>, and <i>Con. sibirica</i>, are newly combined, and two new species, <i>Con. lignicola</i> <b>sp. nov</b>. and <i>Con. fuscoviolacea</i> <b>sp. nov</b>., are described. Through these revisions, the taxonomic positions of several species are clarified, and the paraphyly of sect. <i>Verrucisporae</i> is resolved. In total, this study revises and recognizes 10 new taxonomic entities, including one new section, two new species, and seven new combinations. An identification key to the Chinese species of <i>Conobolbitina</i> is provided, along with morphological descriptions and line drawings for the two new species.