Strumpshaw Fen Slime Moulds & Fungi – September 2025

7th September

We had a super start to September when we found jewel-like translucent, blue-grey slime mould sporangia at the Basecamp loop that we think is Cribraria argillacea.

And after The Outpost some glistening metallic consolidating plasmodia that we also think is Cribraria argillacea.

I’ve posted more about this slime mould.

At Basecamp the Artomyces pyxidatus was still hanging in, not looking to great – desiccating and brittle – but there were some new smaller fruiting bodies.

Near The Outpost some unidentified translucent white slime mould primordia on a fragment of wood.

After The Outpost a Fuligo septica on a section of Birch.

8th September

At the Basecamp loop some sporangia that look like Physarum album on a decaying, mossy section of trunk.

A close up of the sporangia showing them in the process of dehiscing.

At The Dell another Fuligo septica – this one consolidating from plasmodium on it’s way to becoming an aethalium.

The wonderful blobby consolidating plasmodium!

Near The Outpost some unidentified gorgeous young slime mould sporangia. The glistening sporothecae were reflecting the macro LED light!

14th September

On the way to Basecamp some Tubifera ferruginosa at various stages from early stage flesh-pink and salmon to maturing greyish violet.

Just after the Yew trees before The Outpost, on the attached soil of a wind thrown tree root plate, some fungus fruiting bodies that MycoKey’s ID tool suggests could be Paxillus involutus – the brown rollrim.

Close up photo below showing the downy inrolled margin.

MycoKey: Paxillus involutus is a relatively slender, rather pale Paxillus with a downy, inrolled, wrinkled margin. The stem is ± smooth; lacks conspicuous reddish spots or yellow bands. The gills are pale straw-yellow to yellowish-brown and stain brown when bruised; they can be loosened from the pale cap flesh. The spore-deposit is yellow-brown to grey-olive. The smooth spores measure 7–11 × 5–6.5 µm. Mostly mycorrhizal with Picea and Betula, and usually on poor acidic soils. Paxillus filamentosus is more yellow-fleshed and occurs with Alnus. Other species are shorter and thicker-stemmed. Widespread and very common; June–November.

First Nature: The margin remains inrolled – hence the common name Brown Rollrim (or Brown Roll-rim) – and it usually has a fluted edge.

On the downed trunk before The Outpost, where we saw the fabulous Arcyria obvelata display and slime mould plasmodia – at first glance, a grouping of Lycogala aethalia, but this is definitely a fungus. But which one?

MycoKey’s ID tool overwhelming suggests Hypoxylon fragiforme – the Beech woodwart [1]. And certainly in the area around The Outpost there are Beech trees and this trunk section has the diameter that is consistent with what would have been a maturing Beech.

There’s Hypoxylon fuscum [2], but as the common name suggests – the Hazel woodwart – it is almost exclusively on Hazel. But MycoKey, while listing Hypoxylon fuscum in the list of possible IDs, gives it a 0% probability. However, it does suggest a small possibility for Hypoxylon howeanum [3].

While Hypoxylon fragiforme is associated more with Beech trees, Hypoxylon fragiforme can easily be confused with Hypoxylon howeanum:

In the field, H. howeianum can be confused with the very similar H. fragiforme which differs in being usually restricted to Fagus, while the former is plurivorous.

— Pyrenomycetes from France [4]

While examining the photos at home I noticed a likely small primordium of Hypoxylon populated with tiny stalks topped with bead-like heads – undoubtedly a parasitic fungus.

https://www.mushroomexpert.com/fungionwood/puffball%20and%20cushion/species%20pages/Hypoxylon%20fragiforme.htm

Also on the trunk was a crust fungus. I normally ignore these – I find them rather boring unless they have an interesting or compelling morphology.

Back at home, I noticed that this one had toothed projections that had coronate tips (crown-tipped) that made me think of the Artomyces pyxidatus that the daughter and I had been documenting at Basecamp. After some cursory interneting, I’m wondering if this is Sarcodontia uda…?

If you are interested, you can see more examples of Sarcodontia uda at iNaturalist.

The following were all found after The Outpost.

Based on the following two photos, MycoKey suggests 100% that these small fungi are Laccaria laccata – the deceiver mushroom (actually var. pallidifolia).

However, this close up photo of the gills results in a 100% suggestion for Tubaria furfuracea – the scurfy twiglet. If you look closely at the top of the stem, it’s hard to say – is there a faint ring zone? A ring zone is an identifying feature of Tubaria furfuracea [5].

What was interesting – examining the photos back home – was the tiny, emerging, translucent, pale‑yellow, ovoid mushroom.

More unidentified, young, white slime mould sporangia.

Rooting around at the bench just after the Outpost, I came across something that looked like a slime mould that I had not seen before – exciting!

But what about those curious brown, seed-like structures from which the fruiting bodies were emerging? Of course – they were sclerotia, and these were fungi fruiting bodies! An image search quickly indicated that these were a Typhula species.

But which one? Based on macroscopic features, it could be one of several species – and then I read that Typhula quisquiliaris is otherwise known as the bracken club.

And indeed, the entire reserve woodland gets covered with bracken. Looking at the photos again, it was clear to me that these fungi were growing on an herbaceous substrate that looked very much like a fragment of bracken stem.

A “Fieldnote” Alt Text Template
Use this formula: [Morphology/Colour] [Structure] on [Substrate fragment].
e.g. “Brown, seed-like sclerotium on a bracken stem fragment.”

And lastly another Fuligo septica, this one a young aethalium with the reticulate mesh-like cortex.

[1] Hypoxylon fragiforme
Danish Fungal Atlas (MycoKey)Hypoxylon fragiforme page: https://svampe.databasen.org/taxon/15233
First Nature Hypoxylon fragiforme page: https://www.first-nature.com/fungi/hypoxylon-fragiforme.php

[2] Hypoxylon fuscum
Danish Fungal Atlas (MycoKey) Hypoxylon fuscum page: https://svampe.databasen.org/taxon/15235
First Nature Hypoxylon fuscum page: https://www.first-nature.com/fungi/hypoxylon-fuscum.php

[3] Danish Fungal Atlas (MycoKey) Hypoxylon howeanum page: https://svampe.databasen.org/taxon/15237

[4] Pyrenomycetes from France Hypoxylon howeanum page: http://pyrenomycetes.free.fr/hypoxylon/html/Hypoxylon_howeianum.htm

[5] First Nature Tubaria furfuracea page: https://www.first-nature.com/fungi/tubaria-furfuracea.php

Note: Some of the older research sites I link to (like pyrenomycetes.free.fr) don’t use modern security certificates because they are older archives. They are usually safe to browse, but your browser might give you a ‘Not Secure’ warning!