A note on the polarity of Armillea mellea

Abstract

The external appearance of 120 single-spore isolates from a basidiocarp of Armillariella me/lea was characterized by abundant white raised aerial mycelium, and differed markedly from that of the majority of a number of other isolates made from rhizomorphs and basidiocarps collected in nature. These had dark crustose areas and were generally without aerial mycelium. Both types of mycelia lacked clamp connections. Their appearance did not change during two years' cultivation. Crustose mycelia were obtained by pairing single-spore isolates. The pairing reaction followed a tetrapolar pattern. Both types of mycelia had only one nucleus in the terminal cells of the hyphae. In older parts of the mycelium, especially in rhizomorphs, the number of nuclei per cell often exceeded 10. In basidiocarps collected in nature, distinctly dicaryotic and clamped hyphae were met with, especially at the bases of basidia. Various explanations are suggested for the monocaryotic condition of the hypha! tips. As hypha! tip isolations from crustose mycelia obtained by pairing single-spore isolates, regularly ga e only crustose m ycelia, it is possible that the nuclei in the tips of the hyphae area diploid.