Selwyns Wood

I joined the Sussex Fungus Group foray at Selwyns Wood last weekend. This is a Sussex Wildlife Trust nature reserve which I don't think I've ever been to before, so I thought I'd better rectify that. We were met by Trevor Hince, the Volunteer Reserve Manager, who had very kindly offered to take us round.

The first part of our route took us through mixed woodland, where we found The Deceiver Laccaria laccata popping up in various places...

... Along with it's more bohemian cousin, the Amethyst Deceiver Laccaria amethystina.

I was thrilled to see the Parasitic Bolete Mushroom Pseudoboletus parasiticus: a species I've not come across before.

It's easy to identify because it grows from the base of Common Earthball Scleroderma citrinum.

We were under instructions from the Sussex Wildlife Trust ecologist, Graeme Lyons, to look out for Rutstroemia echinophila, a brown disc-shaped ascomycete that grows on last year's Sweet Chestnut husks. And here it is:

I think Graeme said there was a cool vernacular name for it, like Hairy Nut Cup, or something. But I've forgotten it.

Nick Aplin also found this, which he identified as the rather scarce Plicatura crispa.

When we spotted this faded yellow Russula, I thought it would be a good opportunity to try out my new iron sulphate crystal (which has a pleasing resemblance to kryptonite).

The genus Russula (the Brittlegills) contains many very similar-looking species and you have to observe them very closely to be confident of an identification. One of the features you can observe, which is well documented in Geoffrey Kibby's new 'Mushrooms and Toadstools of Britain & Europe Volume 1', is the reaction of the fruit body to chemicals such as FeSO₄: iron sulphate. Some Russula fruitbodies will display a colourful chemical reaction when rubbed with an iron sulphate crystal, turning shades of green, yellow, orange or pink.

I rubbed the stem with my crystal, as if it were a magic lamp, and wished for a spectacular reaction.

Slowly – in a not-very-impressive way, if I'm honest – the stem turned a sort of pinky-brown color, where I'd rubbed it.

Others in the group identified this Russula as the Ochre Brittlegill Russula ochroleuca; and we moved on.


I wish now I'd taken a specimen, as it turns out the fruitbody might have done something more spectacular if I'd applied KOH to the base of the stem: i.e. turn BRIGHT RED!

Reproduced from 'Mushrooms and Toadstools of Britain & Europe Vol. 1' by Geoffrey Kibby

I should have also given it a sniff, as there's another similar-looking species which smells of pelargoniums (geraniums). It seems I wasn't really at the top of my fungal observation game last weekend and, after a busy week, I've forgotten some of the details of what we saw / sniffed. Really must write things down!

Rounding the corner, we emerged in an area of heathland, which was a nice surprise.

I didn't note much here fungus-wise. But we did find this Brown Rollrim Paxillus involutus. You can see where it gets its vernacular name.

From there we moved into an area of Sweet Chestnut coppice which proved to be the most fruitful habitat of our foray.

False Deathcap Amanita citrina popped up in a few places, with its odour of raw potatoes.

There were a few birch trees around, at the edge of the Sweet Chestnut coppice, and we made this Brown Birch Bolete Leccinum scabrum. The dark scales on the stem are a key feature of that species.

The stem flesh showed no hint of blue when cut.

All through the Sweet Chestnut coppice there were little red Russulas popping up through the moss that covered the old coppice stools. I sadly failed to get a photo of these. I'm also rather disappointed I didn't get a photo of Janet's face when she tasted one. 

Growing amongst the leaflitter, we came across this rather non-descript-looking mushroom which Nick persuaded me to take as a specimen, to see if I could get any sense out of it down the microscope. I forgot to take a photo in situ, so this is what it looks like after it's been sitting in my fridge for a week.

It's kept remarkably well. Up close, the wooly ('floccose') stem looks quite distinctive. The cap, too, looks like it was covered in fine, silky (?) hairs.

Under a hand lens or stereomicroscope, you can see the mouse-brown gills have a white edge to them.

I think Nick gave me a clue about what genus we're in here, but I didn't write it down (what was I doing?!). So let's see where MycoKey takes us...

Psathyrella

OK, so, the first question in the key to the Psathyrella in Funga Nordica asks if the spores are > 9μm or < 9 μm. I haven't got a spore print, because the mushroom has been sitting in a box in my fridge for a week. So I'll have to make do with measuring the spores from a gill squash.

I've measured ten spores and I make them all about 9 μm. This is not a good start.

Not wanting to admit defeat at such an early stage, I've decided that - if there's anything in it - the spores are probably a fraction under 9 μm; rather than over. This takes me to a question on whether 'pleurocystidia' (cells on the face of the gills) are present or absent. Yikes! I think this means I'll have to try and look at a cross section through the gill: a gill trama squash. Tricky...

I'm pretty sure I can see pleurocystidia on the face of the gill, but they're rather difficult to see with all those spores washing around.

 
I thought I'd try staining a gill trama squash, and see if that makes the pleurocystidia any easier to see.

YES! This is a cross section of one of the gills at relatively low magnification (100x). I've stained it with PlaqSearch, which was recommended to me as a good, safe, general purpose stain, and then washed it back through with water. On the left hand face you can see lots of vaguely skittle-shaped cells which actually haven't taken up the stain particularly strongly. I think these are pleurocystidia.

Here they are at 400x magnification. Is that 'incrusting' that I can see on them?

Anyway, back to the key.

Now I've got to see if the gill edge and cystidia are "covered in drops staining green in a solution of ammonia." I did this the other day. I can do this!

It hasn't stained green.

This takes me to the following entry in the key:

• Veil absent; pleurocystidia with crystals
• Veil present; pleurocystidia with or without crystals

Hmm. This is where I wish I'd more closely observed the mushroom when it was fresh. When you look closely at the edge of the cap, there is something which looks like it could be the remains of a veil.

And crystals. Hmm... that must be what I observed above: pleurocystidia with crystals. I'll go with the second option: "Veil present; pleurocystidia with or without crystals."

I don't think this mushroom smells "sweetish"; so now I have to look at the shape of the pleurocystidia.

Hmm. This is really tricky. I'm going to go to key J: "Pleurocystidia lageniform to conical, upper part often acute."

This takes me to Psathyrella cotonea, but – looking on vielepilze.de – that doesn't seem right to me. 

*many hours pass, going backwards and forwards through Psathyrella keys...*

I tried mounting the spores in KOH to see if that would help guide me towards an identification. I discovered that the spores turn darker brown in KOH; but it didn't really help!

 
I've now trawled through various other possibilities (P. fibrillosa, P. impexa, the list goes on!) and I think it's time to admit I'm stuck with this one. Nick Aplin also took a specimen, so here's hoping he managed to get to an ID.


As we headed back towards the car park, we had a sudden rush of gorgeous Cortinarius species. I generally steer clear of attempting to identify Cortinarius (Tuula Niskanen's talk at Kew last year rather scared me off) so it was nice to be introduced to these beauties.

Saffron Webcap Cortinarius croceus

Frosty Webcap Cortinarius hemitrichus

And finally, the Surprise Webcap Cortinarius semisanguineus.

 Why is it a surprise? You may well ask. Here is Nick Aplin, about to do the big reveal...

 It's got bright red gills! Crazy!

The walk back to the car park produced a few more species for the list, including Fly Agaric Amanita muscaria popping up through the moss.

And another parasitic species: Silky Piggyback Asterophora parasitica, which grows on decaying Russulas.

Those are just a few of the highlights for me. Both Nick Aplin and Ted Tuddenham took specimens away to check under the microscope, so it's possible a few of the field identifications I've mentioned above may change.

If you'd like to see the full list from this Sussex Fungus Group foray, then sign up to the Sussex Fungus Group Yahoo! group.

For the record
Date: 16 September 2017
Location: Selwyn's Wood
Grid reference: TQ5520

Records will be submitted by Nick Aplin, on behalf of Sussex Fungus Group