Atomic Shrimp - Don't Eat This! - The Yellow Stainer

Don't Eat This! - The Yellow Stainer

What Happens If You Eat This

This is listed as a poisonous fungus in all the books - it's not an especially dangerous one - probably not deadly, but the symptoms of poisoning (which don't always affect everyone) sound deeply unpleasant - any or all of: sweating, hot flushes, abdominal cramps, nausea and vomiting.

However, the inky, soapy flavour is likely to put most people off eating it, but one mushroom in a mixed basket could be masked by the flavour of the others, but could still be enough to cause poisoning - that's why all of the mushroom pages on Atomic Shrimp carry this warning:

Identification Of Wild Fungi

The description here is not intended to be sufficient for conclusive identification of these wild fungi - the reader should understand that the possible outcomes of misadventure with wild-gathered fungi include serious illness and death.

IT IS YOUR OWN RESPONSIBILITY to take adequate steps in identifying any fungi you gather for the table - doubly so if you are intending to share them with someone else.

Informal descriptions, such as the one on this page, are not adequate for full identification - it's just good sense to independently verify everything you read here.

Rules of thumb or folk wisdom identification methods are frequently unreliable.

Consult a comprehensive identification guide (I recommend RogersMushrooms.com and Wild Mushrooms Online) or best of all, talk to a living human expert mycologist.

Not For Sale: End Human Trafficking & Slavery

A load of mushrooms sprang up right in my garden - at first, I thought I had a good crop of Wood Mushrooms. My excitement turned to disappointment, however, when the fungi proved to be specimens of The Yellow Stainer.

What Is The Yellow Stainer?

Agaricus xanthodermus - this close relative of field mushrooms and horse mushrooms is similar in initial appearance to both and so is possibly one of the most likely candidates for accidental poisoning, if you're not careful with the identification.

It has the characteristic Agaricus look - white, slightly scaly cap and pinkish gills that darken to chocolate.

The smell is quite a useful diagnostic - unlike the mushroomy or aniseed scents of some other species in this genus, the Yellow Stainer has a rather unpleasant soapy, inky smell.

Here's a hint of the other key diagnostic - from which the fungus draws its common name - yellow staining.

When picked, the base of the stem is often already marked with deep chrome yellow patches, but all white parts of the mushroom turn yellow quite quickly when scraped or crushed.

Breaking the cap of the mushroom or cutting it with a sharp knife doesn't always reveal the yellow staining staight away - although it will usually appear after a few minutes exposure to air.

A cross-sectional cut through the stem, however, will turn deep yellow straight away.

Here's another look at a broken piece of cap - it wasn't initially showing any yellow staining, but the colour appeared immediately upon bruising the flesh with the point of a knife.

So... that's the description - and you should not eat this - for details of the reasons why not, take a look at the side column.

Comments: 2 (Add)

Some other Agaricus species do exhibit similar yellow staining (A. placomyces, for example) - however, this also is inedible. So yellow staining is a fair diagnostic of non-edibility, but should not supplant positive identification of the species, which is the crucial thing, really.

Good point on picking the stem base - it's important to observe it to aid in the identification. Once I've done the identification (in the case of edible fungi) I prefer to cut the base off the stem before putting the mushroom in the basket - especially with larger specimens, as dirt falling off the base may prove impossible to pick out of the gills later.

Posted by Mike (for Atomic Shrimp) on Sep 24 2010 at 22:21

When collecting any wild mushrooms, the whole stem should be picked as the base of the stem is often critical in the correct identification, particularly in the case of specimens of the Amanita genus. With Yellow Stainers, cutting through the very base of the stem will cause it to immediately colour bright chrome yellow. No other members of the Agaricus mushrooms show this reaction.
I recommend the fungi forum on www.wildaboutbritain.co.uk for ID purposes.
Happy (and safe) foraging.

Posted by Charlie on Sep 24 2010 at 01:19

	All submissions are subject to moderation and editorial change where appropriate.
Name:
Comment:
Enter	[?]