A taxonomic study of the Subantarctic Piptoporus (Polyporaceae, Basidiomycetes) II

Morphological and cultural studies of Polyporus maculatissimus and P. portentosus are presented. Neolentiporus gen. nov. is proposed to accommodate P. maculatissimus , a species with a striking macromorphological similarity with the north temperate P. squamosus . The new genus is characterized by medium to large stipitate fruitbodies with a poroid hymenophore, circular to flabellate pilei with a scaly surface and an excentric or lateral stipe that sometimes is reduced to a short, robust umbo. The hyphal system is dimitic with clamped, irregularly thick-walled generative hyphae that do not react with cresyl-blue, and terminal, unbranched, thick-walled skeletal hyphae that are strongly metachromatic in cresyl-blue. Spores are cylindric, hyaline, thin-walled, inamyloid and binucleate. The sexuality is bipolar, the nuclear behavior is astatocoeno-cytic and the associated wood-rot is brown. The new genus is regarded as the poroid counterpart of the agaricoid Neolentinus. Polyporus portenrosus is included in Laetiporus on the basis of its yellowish fruitbodies, its soft, punky context, its hyphal system composed of simple septate generative hyphae and binding hyphae, its holocoenocytic nuclear behavior and its associated brown wood-rot. A new code symbol, i.e. '9s' is proposed to codify the presence, in cultures, of simple-septate generative hyphae with irregularly thickened walls.