BIOSYSTEMATIC STUDIES ON PHLEBIA-ACERINA, P-RUFA, AND PINUS-RADIATA IN NORTH-AMERICA

Three closely related species, Phlebia rufa, P. acerina, and P. radiat a, were analyzed with molecular, morphological, genetic, and physiolog ical methods. Emphasis was placed on the phenotypically similar taxa P . rufa and P. acerina. Phlebia acerina is common and widely distribute d in North America, but P. rufa occurs only in Washington, Oregon, and British Columbia. Although often considered conspecific, P. acerina a nd P. rufa are intersterile. In addition, differences in basidioma and cultural traits support their separation. At the molecular level, the se species differ slightly in sequence of an internal transcribed spac er of the nuclear ribosomal DNA repeat and a part of the large mitocho ndrial rRNA gene. Restriction maps of the small mitochondrial rRNA gen e and flanking regions provide further evidence that the species are d istinct but closely related. This report includes basidioma and cultur al descriptions of both species. Phlebia radiata is genetically distin ct but shares many morphological and molecular traits with P. acerina and P. rufa. Cladistic analyses of molecular data showed that the thre e taxa are closely related relative to the outgroup taxa P. ludovician a and P. subochracea.