title: Taxonomic reconsideration of a sequestrate fungus, Octaviania columellifera, with the proposal of a new genus, Heliogaster, and its phylogenetic relationships in the Boletales.
abstract: During taxonomic revision of genus Octaviania in Japan we examined herbarium and fresh specimens of O. columellifera and O. asterosperma sensu S. Yoshimi & Y. Doi with morphological and molecular techniques. These two species were identical in both macro- and micromorphological characters and were clearly different from the generally known O. asterosperma. The identity of the two species and their distinctness from O. asterosperma was further supported by both nuclear large subunit and ITS rDNA phylogeny. The molecular analyses also revealed that O. columellifera shares its lineage with the boletoid mushroom-forming Xerocomus chrysenteron complex and that it does not form a monophyletic clade with other Octaviania species. Our morphological reevaluation, including transmission electron microscopic observation of basidiospores, clarified the taxonomic boundary between O. columellifera and other Japanese Octaviania species. Accordingly we propose a new genus, Heliogaster, for O. columellifera with designation of the lectotype. We discuss phylogenetic relationships with Octaviania sensu stricto species and the closely related boletoid (pileate-stipitate) fungi, generic characters of Heliogaster and intraspecific phylogeny.
authors.affiliation: Department of Agrobiology, Graduate School of Agriculture, Tottori University, 4-101 Koyama-cho-minami, Tottori 680-8553, Japan. h_-berg-_f@io.ocn.ne.jp
authors.forename: Takamichi
authors.initials: T
authors.lastname: Orihara
authors.forename: Fumiko
authors.initials: F
authors.lastname: Sawada
authors.forename: Shiho
authors.initials: S
authors.lastname: Ikeda
authors.forename: Masahide
authors.initials: M
authors.lastname: Yamato
authors.forename: Chihiro
authors.initials: C
authors.lastname: Tanaka
authors.forename: Norihiro
authors.initials: N
authors.lastname: Shimomura
authors.forename: Makoto
authors.initials: M
authors.lastname: Hashiya
authors.forename: Koji
authors.initials: K
authors.lastname: Iwase
mesh_terms: D001487:Basidiomycota / Q000145:classification* / Q000235:genetics / Q000648:ultrastructure; D004271:DNA, Fungal / Q000032:analysis; D021903:DNA, Ribosomal Spacer / Q000032:analysis; D007564:Japan; D008969:Molecular Sequence Data; D016533:Mycological Typing Techniques; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D013172:Spores, Fungal / Q000648:ultrastructure
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer