Inocybe

Abstract: SUMMARY A study was conducted to determine if ectomycorrhizal fungi in an age sequence of jack pine (Pinus banksiana Lamb.) stands which had regenerated following wildfire disturbance followed a successional pattern. Ectomycorrhizal development and number of symbionts were assessed in the forest floor and 0-20 cm deep mineral soil in 6, 41, 65 and 122-yr-old stands by conducting a macrofungal fruit body survey and examining pine root tips microscopically for mycorrhizal status and types of fungi forming the symbiosis. The majority of roots were located in the mineral soil with no substantial invasion of the forest floor except in the 122-yr-old stand. Over 90 % of the jack pine root tips were mycorrhizal and the majority of fruit bodies were produced by ectomycorrhizal species, regardless of stand age. There was no decrease in ectomycorrhizal colonization of roots with stand age. Both fruit body and root assessments revealed a distinct sequence of mycorrhizal fungi with stand age consisting of early-stage fungi [Coltricia perennis (L: Fr.) Murr., Thelephora spp., E-strain]; multi-stage fungi [Suillus brevipes (Pk.) Kuntze, Inocybe spp., Cenococcum geophilum Fr., Mycelium radicis atrovirens Melin] and late-stage fungi [Cortinarius spp., Lactarius spp., Russula spp., Tricholoma spp., Hygrophorus spp., Hydnellum peckii Banker, Suillus tomentosus (Kauff.) Sing., Snell & Dick, Piloderma byssinum (Karst.) Jul. and Sarcodon scabrosus (Fr.) Karst.]. Many of the basidiomycete species fruiting above ground were detected also on the roots below ground. Fruit bodies of 50 species of ectomycorrhizal fungi were recorded while 39 distinct mycorrhizal types were identified on the roots. There was a significant increase in mycorrhizal species richness between the 6 and 41-yr-old stands and this was primarily the result of partial replacement of Suillus brevipes on the 6-yr-old trees by late-stage fungi in the older stands. Very few species present in the 6-yr-old stand were completely replaced in the older stands; rather, the multi-stage species present in the young stand were joined by late-stage species in the mature stands. The species abundance distribution of fungi on the roots in the 6-yr-old stand was best described by a geometric series which is typical of an early successional community while the distributions in the three oldest stands conformed to a lognormal series which is indicative of a stable, species rich community. Both the composition and structure of the ectomycorrhizal community had stabilized 41 yr after wildfire.

Abstract: An investigation of mushroom phylogeny using the largest subunit of RNA polymerase II gene sequences (RPB1) was conducted in comparison with nuclear ribosomal large subunit RNA gene sequences (nLSU) for the same set of taxa in the genus Inocybe (Agaricales, Basidiomycota). The two data sets, though not significantly incongruent, exhibit conflict among the placement of two taxa that exhibit long branches in the nLSU data set. In contrast, RPB1 terminal branch lengths are rather uniform. Bootstrap support is increased for clades in RPB1. Combined data sets increase the degree of confidence for several relationships. Overall, nLSU data do not yield a robust phylogeny when independently assessed by RPB1 sequences. This multigene study indicates that Inocybe is a monophyletic group composed of at least four distinct lineages—subgenus Mallocybe, section Cervicolores, section Rimosae, and

Abstract: Nitrogen isotope values (δ15N) are higher in ectomycorrhizal fungi than in their plant hosts but the wide variability in δ15N among sporocarps of different fungal taxa is unexplained. We propose that fungal δ15N reflects sequestration of fungal nitrogen to build fungal biomass, and should accordingly reflect fungal exploration strategies and hyphal properties. To test this, we compared δ15N to exploration types, hyphal hydrophobicity, and the presence of rhizomorphs in ectomycorrhizal species from surveys at four sites in temperate and boreal coniferous forests. Fungi with exploration types of high biomass, such as long-distance (e.g., Suillus), medium-distance mat (e.g., Hydnellum), and medium-distance fringe (e.g., Cortinarius) were 4–7‰ more enriched in 15N than fungi with exploration types of low biomass [medium-distance smooth (e.g., Amanita), short-distance (e.g., Inocybe), and contact (e.g., Hygrophorus)]. High biomass types comprised 79% (Aheden, northern Sweden), 65% (Deer Park, Pacific Northwest, USA), 45% (Stadsskogen, central Sweden), and 39% (Hoh, Pacific Northwest, USA) of ectomycorrhizal species, with these types more prevalent at sites of lower nitrogen availability. Species with hydrophobic hyphae or with rhizomorphs were 3–4‰ more enriched in 15N than taxa with hydrophilic hyphae or without rhizomorphs. The consistency of these patterns suggest that δ15N measurements could provide insights into belowground functioning of poorly known taxa of ectomycorrhizal fungi and into relative fungal biomass across ectomycorrhizal communities.