Abstract
Four species of Haploporus, H.angustisporus, H.crassus, H.gilbertsonii and H.microsporus are described as new and H.pirongia is proposed as a new combination, based on morphological characteristics and molecular phylogenetic analyses inferred from internal transcribed spacer (ITS) and large subunit nuclear ribosomal RNA gene (nLSU) sequences. Haploporusangustisporus, H.crassus and H.microsporus occur in China, H.gilbertsonii occurs in the USA, and the distribution of H.pirongia is extended from New Zealand to Australia. Haploporusangustisporus is characterized by the distinct narrow oblong basidiospores measuring 10.5-13.5 × 3.9-5 µm. Haploporuscrassus is characterized by the presence of ventricose cystidioles occasionally with a simple septum, dissepimental hyphae usually with a simple septum, unique thick-walled basidia and distinctly wide oblong basidiospores measuring 13.5-16.5 × 7.5-9.5 µm. Haploporusgilbertsonii is characterized by its large pores (2-3 per mm), a dimitic hyphal structure with non-dextrinoid skeletal hyphae and wide oblong basidiospores measuring 12-15 × 6-8 µm. Haploporusmicrosporus is characterized by distinctly small pores (7-9 per mm), the presence of dendrohyphidia, and distinctly small ellipsoid basidiospores measuring 5.3-6.7 × 3-4.1 µm. Haploporuspirongia is proposed as a new combination. Haploporusamarus is shown to be a synonym of H.odorus and Pachykytosporawasseri is considered a synonym of H.subtrameteus.