Mushroom of the Month - January 2010

Winter is not the best time for cap-and-stem fungi, but if we get a mild spell there is a group of fungi ready to spring forth in woodland - the Cortinarius mushrooms. I am using the term 'mushrooms' in the broadest sense rather than in its narrow 'edible-fungi' interpretation, because many Cortinarius species are known to be poisonous - some of them deadly - and nearly all others are of dubious or unknown edibility. For that reason the total number of Cortinarius species that I can recommend for eating is... zero. These are look-at-me mushrooms, and not feast-on-me fungi.

Cortinarius cinnamomeus is a wonderful winter woodland species, as it generally appears quite late in the autumn and often fruits through the New Year and occasionally into February. It's also a very distinctive mushroom, unlike most species in this difficult group.

In the UK I find this gregarious mushroom most often in coniferous woodland, but it is also found under birches in dry heaths. All Cortinarius fungi are mycorrhizal (they form symbiotic associations with the roots of trees), so they do not occur in grassland (at least not significantly beyond the point where tree roots extend into the fields).

For identification details see the fungi section of http://www.first-nature.com/ where this and several related species are pictured and described.

Here's another picture of Cortinarius cinnamomeus:

One final point about winter mushrooms... after heavy frost it's generally a week or ten days before any new fruitbodies emerge from the forest floor, but some of the wood rotters and parasites that grow on trunks and branches cope much better with the cold.

Happy New Year, and happy fungi hunting!