Classification and phylogenetic relationships of Hymenochaete and allied genera of the Hymenochaetales, inferred from rDNA sequence data and nuclear behaviour of vegetative mycelium

Abstract

Based on nuclear rDNA sequences of 18 species of the corticioid genus Hymenochaete, one species of the stipitate Stipito- chaete, two species of the hydnoid Hydnochaete, one species of the hydnoid Asterodon, two species of the cyclolamellate to poroid Cyclomyces, two species of the cyclolamellate to poroid Coltricia and 11 more species of the poroid Hymenochaetales, we examined the position of Hymenochaete within the Hymenochaetales, the infrageneric structure of Hymenochaete, and the relationships between Hymenochaete, Stipitochaete, Hydnochaete, Cyclomyces and Coltricia. In addition, the nuclear behaviour of the vegetative mycelium was studied for 10 selected taxa of Hymenochaete and one taxon of Hydnochaete. Hymenochaete appears to be polyphyletic, and a new genus, Pseudochaete, is proposed to accommodate the holocoenocytic H. tabacina, which is more closely related to the poroid Hymenochaetales, Onnia and Porodaedalea. The splitting of Hymenochaete into four anatomically distinct sections is not supported by our data. Stipitochaete is not a separate genus. Hydnochaete duportii and H. japonica, as well as Cyclomyces fuscus and C. tabacinus are not distinctly separated and are suggested to be transferred to Hymenochaete.