Identification and rules of thumb

The key point of the video that inspired the previous post was, "If you don't know what it is, don't eat it".

But how do you actually identify your mushroom, and are there any reliable indicators that the mushroom in question is edible?

Putting a name to a mushroom can be a challenging task, because the fruitbodies that we eat are not the organism itself but merely its reproductive organs. So what we are trying to do here is essentially the same as attempting to identify a mammal by the shape of its... erm... lungs or kidneys. How do we do that?

1. Fungus appearance. A good mushroom guide will list perhaps 30 possible characteristics that need to be looked at, such as cap size and colouring, shape and position of gills, stipe markings, etc. etc.   If you have all day, great, because you'll need it. Don't forget a dictionary. Half of the words won't make sense at first reading.

2. Ecology. Where is the fungus found? As mentioned in the previous post, there are many lookalikes that can fool even an experienced forager if put next to each other, but can still be easily told apart since they form relationships with different trees. For instance, the poisonous woolly milk cap from the previous post is associated with birch, while the delicious saffron milk cap grows under pine.

3. Spores. It is impossible to do a spore print in the field, but completing it greatly improves the chances for correct identification. Just put the spore-bearing part of your fungus over two pieces paper, white and coloured, and wait for 24 hours. If you want to be really thorough, you can also look at the spores under a good microscope, but this will probably take you over the line beyond which a hobby becomes obsession. Keep it healthy. Breathe.

Remember me?

But what if you don't wish to remember all of these details, and do not want to wait for spore prints? Suppose, you have a can of soup to improve NOW! Any, hmm, rules of thumb?

For instance, is the mushroom safe to eat if its cap peels? Or if you find it complete with a slug, happily munching on its stipe? In fact, deathcaps can be eaten by slugs and insects (they are unaffected by the toxins) and have a peelable cap. These are the two most dangerous misconceptions of which I am aware, but all other "edible mushroom indicators" I've come across are at best useless. So, are we definitely stuck with making spore prints?

Not quite. There is a bit of good news. One reliable rule of thumb does exist, and it is based on ecology. There is a habitat where all mushrooms that are to be found are 100% edible, guaranteed.

This place is your local supermarket*, and it is the subject of tomorrow's post.

Image credit: Amanita phalloides and slug, used under the terms of Creative Commons Attribution-Share Alike 3.0 Unported license
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* As with all rules of thumb, this advice is offered "as is", to be used at your own risk. If you do manage to get mushroom poisoning as the result of following it, sue the supermarket. They have more money than me anyway.