Taxonomy and phylogeny of Litschauerella (Hymenochaetales) and Tubulicium (Trechisporales) in East Asia: Three new species and six new records

Litschauerella and Tubulicium are corticioid genera that share distinctive lyocystidia with multiple roots but differ in the chemical reactions and surface ornamentation of these structures, as well as in basidiospore morphology. Their Litschauerellaceael placements have long remained unresolved due to a lack of molecular data for the type species. Here, we present the first nuc rDNA internal transcribed spacer ITS 1-5.8 S-ITS 2 (ITS) sequence for Litschauerella abietis, the type species of Litschauerella, and integrate it with nuc 28 S rDNA (28 S) sequences and morphological re-examination of type materials and new collections from East Asia to infer the phylogenetic placements of both genera.

Phylogenetic analyses based on combined ITS and 28 S datasets using Bayesian inference and maximum likelihood methods confirm that Litschauerella forms a monophyletic, well-supported clade within Litschauerellaceae of the Hymenochaetales, representing an early-diverging lineage within the order, whereas Tubulicium is retained within Hydnodontaceae of the Trechisporales, sister to Membranohymenium. Based on morphological and molecular evidence, three new species of Tubulicium are described from East Asia: T. densum sp. nov., T. fusiforme sp. nov., and T. naviculisporum sp. nov.

Additionally, five species are newly recorded for Taiwan (L. abietis, T. bambusicola, T. curvisporum, T. dussii, and T. vermiferum), and L. hastata is reported as a new record for Vietnam. Updated identification keys are provided for both genera.