Phylogenetic relationships of Asterodon and Asterostroma (Basidiomycetes),two genera with asterosetae

The occurrence of asterosetae in Asterodon and Asterostroma suggests a clos e relationship of these genera, whereas other morphological and anatomical features point at a polyphyletic origin. Using a dataset of 26 taxa, the re lationships and the assignments of Asterodon and Asterostroma are studied b y molecular sequence data of a region of the large subunit of the nuclear e ncoded ribosomal DNA. Taxon sampling includes representatives of the Hymeno chaetales, the Lachnocladiales, the Russulales and the Polyporales. Accordi ng to the phylogenetic analysis, Asterodon and Asterostroma are not closely related. Asterodon is evidently placed within the Hymenochaetales. A siste r group to this genus was not found with confidence within the hymenochaeto id taxa included in this study. Asterostroma is placed in the Lachnocladial es, close to Vararia and Dichostereum. The two evolutionary lineages, Aster odon and Asterostroma, in which asterosetae convergently occur, are discuss ed referring to morphological and anatomical characteristics.