Ectomycorrhizal fungi associated with aspen on three sites in the north-central Rocky Mountains

Abstract

Sporocarps of ectomycorrhizal fungi were collected over three field seasons in aspen (Populus tremuloides) stands in the Rocky Mountains, 1800–2000 m above sea level. The two sites in southwestern Montana and one site in southeastern Idaho vary in size, age of trees, type of soil, drainage patterns, and to a certain extent, climatic conditions. In all, 43 species of ectomycorrhizal fungi were found associated with aspen. The Cortinariaceae were a dominant component of the mycoflora, including at least seven species of Inocybe. Fourteen species of ectomycorrhizal fungi, including Leccinum aurantiacum, occurred on all three sites in association with aspen, and the dominant or characteristic mycorrhizal species varied among sites. The early colonizers Inocybe lacera and Laccaria laccata, which were previously reported on acidic soil, were characteristic of the smelter-acidified, nutrient-poor soil of the site near Butte, Montana. Late stage fungi such as Amanita muscaria and Lactarius controversus were more prevalent in the older, undisturbed aspen stands. Key words: aspen, ectomycorrhizal fungi, mycorrhizal fungi, Populus tremuloides.