Willow Blister - Cryptomyces maximus
A stroma is formed over a Salix branch, dark grey/black in colour, often with a bright yellow margin.
host 
Photographs needed of the species in its habitat. Note substrate and associated plant species. This is a rare species, and we recommend that it is verified from a specimen by an expert before submission to NatureSpot.
Willows (Salix)
Rare
The 2025 records at Rutland Water are the first VC55 records
It is the only native British species which features in the 'Top 100 Most Threatened Species in the World' list that the IUCN and ZSL produced – see Baillie, J.E.M.; Butcher, E.R. 2012. Priceless or Worthless? London, Zoological Society of London.
Also see entry on The Global Fungal Red List
David Nicholls
Rutland Water, Egleton
08 June 2025
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MAP KEY:
Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2025+ | 2020-2024 | pre-2020
UK Map
Species profile
- Common names
- Willow Blister
- Species group:
- fungus
- Kingdom:
- Fungi
- Order:
- Rhytismatales
- Family:
- Rhytismataceae
- Records on NatureSpot:
- 1
- First record:
- 08/06/2025 (Nicholls, David)
- Last record:
- 08/06/2025 (Nicholls, David)
Total records by month
% of records within its species group
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