Studies on the Paxillus-involutus-complex.

The Paxillus involutus complex is studied with emphasis on European and Nor th American species. Morphological and anatomical features are described an d details of fruitbody anatomy (trama of cap, gills and stipe, hymenium of gills and stipe), rhizomorphs, sclerotia, and cystidia of soil mycelia are depicted in detail. Amplification of DNA with the Polymerase Chain Reaction (PCR) is applied, and Restriction Fragment Length Polymorphisms (RFLP) are analysed, too. The surface of spores is investigated by Scanning Electron Microscopy (SEM). Comprehensive own observations and literature data are us ed to discuss the ecology of Paxillus involutus s.l. which includes the new European species Paxillus validus and P. obscurosporus as well as P. albid ulus, P. involutus s.str., P. rubicundulus and P. vernalis. A detailed disc ussion is included why the name P. rubicundulus should be used for the Euro pean Paxillus species associated with Alnus. A synoptic table compares the most important features of these six species.