Beschreibung:
<jats:title>Abstract</jats:title><jats:p>Ericaceous dwarf shrubs including <jats:italic>Calluna vulgaris</jats:italic> and <jats:italic>Vaccinium</jats:italic> spp. occur both in open heathland communities and in forest ecosystems as understorey vegetation. Ericaceous shrubs were once thought to form ericoid mycorrhizal associations with a relatively narrow range of ascomycetous fungi closely related to, and including, <jats:italic>Rhizoscyphus ericae</jats:italic>. However, perceptions have recently changed since the realization that a broader range of ascomycete fungi, and in some cases basidiomycete fungi, can also form associations with the roots of ericaceous plants. We used a combination of molecular approaches, including denaturing gradient gel electrophoresis, terminal restriction fragment length polymorphism, cloning and sequencing, to investigate the diversity of fungi associated with <jats:italic>C. vulgaris</jats:italic> roots collected across a heathland/native Scots pine forest vegetation gradient. We also determined differences in fungal community composition between roots of co‐occurring <jats:italic>C. vulgaris</jats:italic> and <jats:italic>Vaccinium myrtillus</jats:italic> in the forest understorey. Collectively, the data show that a large diversity of potentially ericoid mycorrhizal fungal taxa associate with roots of <jats:italic>C. vulgaris</jats:italic> and <jats:italic>V. myrtillus,</jats:italic> and that ascomycetes were about 2.5 times more frequent than basidiomycetes. The assemblages of fungi associated with <jats:italic>C. vulgaris</jats:italic> and <jats:italic>V. myrtillus</jats:italic> were different. In addition, the community of fungi associated with <jats:italic>C. vulgaris</jats:italic> hair roots was different for samples collected from the forest, open heathland and a transition zone between the two. This separation was partly, but not entirely, due to the occurrence of typical ectomycorrhizal basidiomycetes associated with the hair roots of <jats:italic>C. vulgaris</jats:italic> in the forest understorey. These data demonstrate that forest understorey ericaceous shrubs associate with a diverse range of ascomycete and basidiomycete taxa, including typical ectomycorrhizal basidiomycetes.</jats:p>