New records and new taxa of fungi from the mycorrhizae of terrestrial orchids of Alberta

Abstract

Pure cultures of endophytic fungi were obtained from the mycorrhizae of some native Alberta orchids (Amerorchis rotundifolia, Calypso bulbosa, Coeloglossum viride, Corallorhiza maculata, Platanthera dilatata, P. hyperborea, P. obtusata). Isolates of Rhizoctonia constituted the largest group of endophytes, but few could be identified to species. One of these strains was identified as Rhizoctonia repens, a species reported to be a ubiquitous and common mycorrhizal fungus of orchids. Another strain produced the teleomorph stage and was identified as Ceratobasidium obscurum. Rhizoctonia anaticula Currah, sp.nov. is described based on five isolates bearing monilioid cells linked by prominent, narrow connections. A second group of isolates consisted of sterile, greenish black to grey fungi. After prolonged incubation, eight of these isolates formed conidia. Two isolates produced phialoconidia and were identified as Phialocephala fortinii. Five isolates, demonstrating sympodial development of conidia in the apical region of swollen or unswollen hyaline conidiogenous cells, are disposed in Leptodontidium orchidicola Sigler & Currah, sp.nov. The remaining conidial isolate was identified as Trichocladium opacum. Two isolates, resembling Rhizoctonia in cultural features, sporulated and are described as Trichosporiella multisporum Sigler & Currah, sp.nov.