Agrocybe - The Fieldcaps

Agrocybe is likely to be one of the last groups containing edible species that foragers
will get to know. They are cousins of the shop and field mushrooms (Agaricus) and
could be confused with them. The group itself is a taxonomic headache, especially
the A. praecox "cluster" of species (common name "Spring Fieldcap", although
it appears right through until the autumn.) None of them are all that common,
identifying them isn't always straightforward and some members of the group could
be confused with poisonous species.

The guided session on October 1st was not the easiest, due to the freakishly hot
weather. This made for generally lean pickings - the grassland species were basically
baked dry and the woodland species were struggling to appear in the first place.
However, as is often the case during unusual weather I came across a species I've
never found before: the Poplar Fieldcap (Agrocybe cylindracea.) They too had been
feeling the heat, which is why they are so cracked in the middle. Thankyou to Steve
for the photos.

This fungus is cultivated for food in Asia and used in Chinese medicine.  It is firm and very tasty, and these ones were completely free of maggots.  It can be found all year round, usually in the vicinity of poplars or willows.  It is uncommon, so it is best not to take all of them if you find them, even though you may find quite a lot of them in one place.

The tastiness of this fungus has aroused my curiosity about the edibility of another member of this genus.  Agrocybe rivulosa was described as a new species in 2003, when it turned up growing on woodchips in the Netherlands.  It arrived in the UK shortly afterwards and has been spreading prolifically ever since.  I've seen it about five times, although sadly I have no photographs and none of those on the internet are labelled for re-use.   Given that this is technically an invasive species, there would be no problem in taking as many of them as you like for food…apart from the fact that nobody has any idea whether they are poisonous or what they taste like.  Given that they are closely related to a species which is very tasty, and that none of their relatives are dangerous, I think I may be tempted to trysome next time I come across them.  Or maybe not…

The weather is now returning to something more like normal for October, and there is a good chance that we will get a nice burst of fungal activity before the first frosts kill off the main autumn species.  Happy hunting.


Geoff