PAIRING INCOMPATIBILITY AND OTHER DISTINCTIONS AMONG HIRSCHIOPORUS [POLYPORUS] ABIETINUS, H. FUSCO-VIOLACEUS, AND H. LARICINUS

Abstract

Sporophores from 31 collections from North America and Europe representing the poroid, irpicoid, and lamellate forms of the Hirschioporus abietinus aggregate were used as a source of monokaryons for pairings. Sibling crosses have confirmed published reports on the tetrapolarity of the poroid and irpicoid forms and have shown that the lamellate form is also tetrapolar. Crosses between different collections have demonstrated practically complete incompatibility between the poroid, irpicoid, and lamellate forms. Among the poroid sporophores from North America, two groups have appeared which are incompatible with each other, but both of which are at least partially compatible with the poroid form from Norway. The Canadian collection (DAOM 9517), reported in previous work by Raestad and Robak as "intermediate", is shown here to conform completely with the irpicoid form. The question of the taxonomic value of reported hyphal anastomoses between otherwise incompatible cultures is discussed. On the basis of the evidence from differences in morphology of typical sporophores, growth in culture, and host preferences, as well as incompatibility between collections, it is concluded that the poroid, irpicoid, and lamellate forms are best considered three separate species.