Saturday, 24 June 2017

Copping out

I went to visit a new site today: Broadmare Common, just south of Henfield in West Sussex.

I was pleasantly surprised to discover an intepretation board on my arrival, explaining the history of this area of common land. From the 17th century to the early 20th century it was an industrial area for the digging of clay used to make bricks. It's now managed by the Henfield Conservation Volunteers for people and wildlife to enjoy.

The common boasts a reasonably extensive area of wet woodland and many small ponds, so I thought this might be a good spot to find some fungi during this dry month of June.

There's lots of this sort of thing, so I was glad I had my boots on.

I found a few different ascomycetes and bracket fungi growing around the ponds, plus loads of myxomycetes (slime moulds) from the genus Stemonitis, which I'll come back to later. But it was at the edge of this pond that I found my one and only mushroom for the day.

It was a small, pale and delicate mushroom, growing on what I assumed to be a willow twig. It was very near the edge of the pond, where the ground is probably permanently wet.

I wouldn't normally attempt to identify a little thing like this, but in several respects it seemed quite distinctive, so I thought I would have a go.

The cap was topped with a neat little tan umbo (pointy bit). The cap itself was pale, translucent, and pleated forming radial ridges. Underneath, the gills were a darker mousy brown; the colour was visible through the translucent cap cuticle, giving the cap the appearance of being mousy brown to about 2/3 of its radius. The gills appeared to be free: attached to the cap, around the stipe; not abutting the stipe itself. The stipe was the same translucent white as the cap cuticle, and tan coloured right at the foot of the stipe, above the white mycelial strands which anchored the mushroom to its twig.

I started off down completely the wrong track, thinking it was a Bonnet mushroom one of the Mycena or Marasmius species. But the brown gills meant it must be something different. I eventually realised that this mushroom belongs in one of the Inkcap genera. I'd been fooled by that pale margin, without the slightest hint of deliquescing inkiness; but not all Inkcaps deliquesce, of course.

I flicked through the Collins Fungi Guide, looking for species matching mine which would be found on twigs.

Coprinellus subdisseminatus seemed like an excellent match, but I thought I'd best check its microscopic features against the description in Funga Nordica, to be sure.

This is where I've got stuck. The genus Coprinellus seems to comprise a lot of really rather similar mushrooms. And I wasn't sure I'd managed to find any of the things I was looking for down the microscope.

The first thing I noticed, aside from the brown spores, were these spherical things. What the heck were they?

After much poring over the keys in Funga Nordica, I came to the conclusion they might be 'velar spherocysts' – round things which are found on the cap of some Coprinellus species. 

They did seem to occur primarily in the cap (which I should possible refer to as the 'pileipellis'):

According to Funga Nordica, only some species of Coprinellus have 'velar spherocysts'. C. subdisseminatus is one of the species which is "without velar spherocysts". So I guess my mushroom isn't that after all...

The problem that I had then is, in order to ascertain what species of Coprinellus my mushroom actually is, I needed to get a good look at the cystidia (weird structures which can be found on the surface of the mushroom no one knows what they're for).

There are different names for the cystidia, depending where they're found on the surface of the mushroom. In Coprinellus mushrooms, it seems the ones you need to look out for are:
  • cheilocystidia - cystidia on the edges of the gills
  • pleurocystidia – cystidia on the faces of the gills
  • pileocystidia – cystidia on the surface of the cap
  • caulocystidia – cystidia on the stipe
Funga Nordica also talks about 'sclerocystidia' but that word's not in the glossary and I have no idea what it means.

So, I found some stuff.

There was this:

I guess those rolling-pin type shapes could be pileocystidia.

There was also this:

I have no idea what that is, but it's very pointy.

And I thought I could possibly detect some cystidia here:

... and here:

But, in conclusion, finding cystidia on tiny Coprinellus mushrooms is really hard and I still have no idea what species this is.


For the record
Date: 24/06/2017
Location: Broadmare Common
Grid reference: TQ216150 (site centroid)


  1. Sclerocystidia are not defined in Ainsworth and Bisby dictionary. A google images search found them here where they are illustrated as rather thick edged and craggy looking cystidia in a description of Coprinellus coprinus. The name seems to be used to describe the thick walled cystidia found in some Coprinellus species but has not found its way into the dictionaries and glossaries yet. Thanks for your stimulating blog.

  2. Sorry that should have been Coprinellus callinus. By the way Coprinus and its allies are difficult. In a humorous list of things to say to forayers when offered a specimen one cannot identify was 'Derek would be interested in that' referring to Derek Schaeffer who is a coprinus specialist. So evidently other foray leaders struggle with Coprinus sp.

    1. Thanks Ted. That website looks really helpful. I won't feel too bad about getting stuck trying to identify this Coprinellus then. :)