June 2006. A mushroom sent from Vanuatu and, it was asked, is it edible? The answer from members was interesting: ???Some Agaricus stain yellow and these are not edible; however, the staining can be very slight. Generally botanic gardens will not identify for edibility for legal reasons???.

Other suggestions were: dry some specimens in the hope that an expert can be found and also do a spore print: cut off the stem of an expanded cap and place it on white paper, gills downward, cover with glass beaker and leave over night. Note colour of the sore mass.

A very useful note was provided by Eric Boa, CABI, UK and it is provided here in full.

When not roaming the world for plant diseases I’ve been busy compiling a list of ALL the world’s known useful fungi. We are a cystidium away from getting this on the web with the novel and some might say foolhardy addition of a summary judgment on edibility. ‘We’ is me, and my colleague Miriam de Roman.
I’ve asked Miriam for comments on likely species – she’s much better at field identification. The short answer is otherwise ‘phone a friend’ and take hope they a) know what they’re doing and b) are willing to do an ID. No simple solution.

The summary judgments, by the way, are based on published information and, as we will state on the website about to be launched, are therefore only as good as the original data. But we’ve also decided that sitting on the fence is of little practical assistance and that we need to move on to a more objective method (ate it, didn’t feel sick/die, etc.). Field guides are often unhelpful – if in doubt, leave it out. Or if one person died from eating Paxillus involutus every day for a month then it suddenly becomes ‘deadly poisonous’. You see what I mean.

The attached list of Agaricus spp. and their summary judgments shows the number of records obtained from books, papers and so around the world. Again, I emphasise this is not a final and absolute statement about edibility. But note that ‘food’ means someone has eaten without any reported side-effects. ‘Edible’ simply means that it could be eaten but there was no conclusive proof that the author had tried it themselves.