I saw this big, boxy mushroom in Horton Wood on Saturday. There were a few of them scattered around.
I broke off a section of the cap and crushed it between my fingers, to see if I could detect any smell. I thought I got a hint of marzipan; but it was quite faint.
I noticed that the fragments of cap cuticle I was left with had turned a bright acid yellow. You can see in this photograph that the stipe has also discoloured slightly yellow where I've scraped it. The mushroom has a partial veil; and the young gills are pale.
I think these features – especially the boxy (almost trapezoidal) shape and the yellow staining – make this mushroom the Yellow Stainer Agaricus xanthodermus.
UPDATE 23/08/2017 - I read somewhere, after writing this blog, that a distinctive feature of the Yellow Stainer Agaricus xanthodermus is yellow staining in the very base of the stipe, when it's sliced open. Like this:
|IMAGE reproduced from NatureSpot. © Lostash|
I tried another one, just in case the first one was a dud.
That one didn't stain yellow either.
I finally had to admit: this wasn't a Yellow Stainer Agaricus xanthodermus. I was stuck.
I posted a few photos on Twitter to get another opinion.
Andy Overall (@fungitobewith) sent me some very helpful replies with a couple of possibilities: Agaricus macrocarpus or A. silvicola. Both of which would fit with the features I'd observed and have a faint 'almonds' odour. Andy thought A. silvicola more likely; but microscopy would be needed to be sure.Confused by these mushrooms. I thought boxy shape + yellowing cap = Yellow Stainer. But stem isn't going yellow like it's s'posed to. 🤔 pic.twitter.com/PJdkSQpo3F— Clare (@__clare__) August 13, 2017
Unfortunately other commitments called on my time that week, and I never did get back to Horton Wood to collect some material I could examine under the microscope. So these mushrooms never got a name.
My friend Sasha spotted this grey mushroom growing on a rotting log.
The grey cap leads me to Willow Shield Pluteus salicinus. The book says that its 'free, crowded' gills are 'white, maturing pink'; which looks about right.
There were also masses of Russulas around, but I'm still ignoring those.
For the record
Location: Horton Wood, Small Dole
Grid reference: TQ208127 (site centroid)