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Smutty naked ladies - a new fungus find at Westonbirt

20 July 2013

A rare, endangered, species of fungus has been recorded for the first time in Gloucestershire, at the Forestry Commission’s National Arboretum at Westonbirt.

smutty naked lady fungusThe sooty-black smut fungus Urocystis colchici only infects the leaves of Naked Ladies (Colchicum autumnale) also known as Meadow Saffron or Autumn Crocus (although it is not a true crocus).

The smut-fungus is so called because its spores are a sooty-black colour. These are formed in blister-like sores (sori) on the leaves, each producing hundreds of thousands of minute powdery brown-black spores.

The host plant has this interesting common name because it flowers in the autumn months after the spring leaves have rotted away, thus the flowering plant appears naked.

The fungus was found on a few leaves of a single plant, after an extensive search by Dave Shorten of the Cotswold Fungus Group, who commented:

“It is very exciting to have made a sighting of this extremely rare fungus at Westonbirt Arboretum. The Forestry Commission’s management of the landscape has provided the ideal conditions for the species to survive.”

Urocystis colchici is an extremely rare and legally protected species of fungus. Natural England describes it as a species of “principal conservation importance” in England because of its rarity and potentially threatened habitat.

The British Mycological Society count the fungus as a Critically Endangered species, cited as such on the IUCN Red List of Threatened Species. It also appears on the national Biodiversity Action Plan as a fungus species for conservation.

Very little is known about the fungus and in England it has only been seen twice in the past decade, in Herefordshire and Oxfordshire.

This fungus is a legally protected species and should not be picked, however, if you come across it at Westonbirt Arboretum, please note the identification number of the nearest tree (top-left corner of the tree label) and provide this along with a description of how to find it from there to

Last updated: 10th July 2017

England's Woods and Forests are cared for by Forest Enterprise England, an agency of the Forestry Commission.