About this fungus
Alder Rollrim is a fungus in the Paxillaceae family. Its habitat and field characteristics are summarised below.
A brown to ochre rollrim beneath alder, often on damp ground, with a strongly inrolled young cap edge.
What to check
Confirm alder nearby. Check the decurrent, forked, easily separable gills and their brown bruising. A brown spore print supports Paxillus.
Variation
Caps flatten and become depressed with age, while the margin gradually unrolls. Wet caps are darker and may feel slightly sticky.
Lookalikes
Paxillus involutus is extremely similar and grows with a broader range of trees. Exact separation may need spores and cap-cuticle characters.
Habitat and range
An ectomycorrhizal alder specialist, often found in wet woodland, stream margins and other damp places across temperate regions.
Food safety
Poisonous.
Photographs
Photo: Perry Gunnar Larsen|Heinrich Bosch · CC BY 4.0