STUDIES OF CANADIAN THELEPHORAGEAE: IX. A CULTURAL AND TAXONOMIC STUDY OF THREE SPECIES OF PENIOPHORA

Abstract

Close relationship between Peniophora heterocystidia Burt, P. mutata (Peck) Höhn. & Litsch., and P. populnea (Peck) Burt is indicated by similarities in their fruit bodies, but specific separation is warranted by differences in color and thickness of fruit bodies and in shape and relative numbers of cystidia and gloeocystidia. In addition, P. populnea is restricted to the host genus Populus and P. heterocystidia to broad-leaved trees other than Populus. This separation is confirmed by recognizable differences in the cultural characters of the three species and by interfertility tests. Pairings between monosporous mycelia from individual fruit bodies have shown that all three species are hermaphroditic, self-sterile, and interfertile, and of the bipolar type of interfertility. Pairings between monosporous mycelia from fruit bodies of the same species have shown complete or partial fertility, while pairings between fruit bodies of the different species have demonstrated complete sterility. Cultures from fruit bodies typical of P. allescheri (Bres.) Sacc. & Syd. behaved like those from typical P. mutata, confirming the combination of the two species. In interfertility tests between cultures of P. mutata, isolates from Populus were completely interfertile, as were those from hosts other than Populus, but pairings between isolates from Populus and other hosts exhibited various degrees of incompatibility. Sizes of basidiospores and conidia in collections and cultures of P. mutata from Populus were slightly larger than in collections from other hosts, but differences were not considered sufficiently great to justify the establishment of a variety. Conidiophores and conidia are produced abundantly in cultures of all the species but were found in nature only in two collections of P. heterocystidia.