Zythia resinae (aka Sarea resinae)

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It’s always worth looking at tree stumps, as they can host a range of fungi.

This coniferous stump was in a Norfolk wood and is probably the remains of a Douglas Fir, Pseudotsuga menziesii, for they were planted in the wood as a timber crop, amongst the native deciduous trees. The bottom of one side of the stump was covered in a dark patch of resin.

A tall stump of a conifer in a Norfolk wood (May 2025).

The resin was covered in lots of pinky-orange, stalkless cup fungi, each one about a millimetre in diameter.

Conifer resin covered in light orange cup fungi.

I took some photographs and used a knife to remove a small piece of resin with the fungi attached.

Stalkless cups of Zythia resinae on conifer resin.

Back home, I had a look at the cups under the microscope.

The fungi were clearly cup-shaped ascomycetes (sometimes known as discomycetes), with asci (chambers containing spores) and paraphyses (sterile hairlike filaments).

Paraphyses (sterile filamentous hyphal end cells) of Zythia resinae. x1000, stained with Congo red.

I’m used to asci that contain a small number of moderately sized spores (often eight) but these contained a hundred or more tiny spores, each one roughly two micrometres in diameter.

Two asci of Zythia resinae, containing hundreds of tiny spores, each about 2 micrometres in diameter. x1000, stained with Congo red.

I posted my photos on the “Ascomycetes of the World” Facebook page and the genus Zythia/Sarea was suggested. This led me to identify the fungi as Zythia resinae (also known as Sarea resinae).

My find was a “first for Norfolk”, so I dried and froze a sample of fruitbodies and passed them to the Norfolk Fungus Study Group’s DNA team for DNA extraction and sequencing. The results came back in November 2025, confirming my provisional identification. The fungus will be added to the Fungal Records Database of Britain and Ireland under its current name of Zythia resinae but the DNA sequence will be submitted to Genbank as the older Sarea resinae.

I found the fungi on the stump in mid April and revisited at the end of May, when there were many more fruitbodies, in spite of the dry spring.

Zythia resinae

The genus Sarea was thought to contain two species complexes: the black Sarea difformis and the orange Sarea resinae (both sensu lato). But in 2021 Mitchell et. al. examined the morphology and ribosomal DNA (rDNA) of 70 specimens of Sarea and their conclusions supported the split of Sarea difformis s.lat. and Sarea resinae s.lat. into two distinct genera, with Sarea resinae becoming Zythia resinae (note 1).

Zythia resinae is illustrated in Volume 1 of ‘Fungi of Switzerland’ by its older name of Biatorella resinae (on page 240). It features as Sarea resinae in Volume 2 of Laessoe and Petersen’s two volume “Fungi of Temperate Europe” (on page 1461). Other synonyms are Pycnidiella resinae, Cytispora resinae, Cytospora resinae, Sphaeria resinae and Pycnidiella resinae (note 2).

Zythia resinae is known as Sarea resinae on several websites. Jan Thornhill, who is based in central Ontario in Canada, describes her encounter with the fungus on her enjoyable “Weird and Wonderful Wild Mushrooms” blog (‘”Another Fluke: Sarea resinae”, 23rd March 2014). Nearer to home, Chris and Christine Johnson have some excellent photographs on their “Fungi Outer Hebrides” website. There are some good photographs on the AscoFrance Forum and on the Fungi of Great Britain and Ireland website, as well as in the paper “Sareomycetes: more diverse than meets the eye.” (note 1).

Distribution

There are scattered records for Zythia resinae throughout much of the British Isles.

Zythia resinae can also be found in many European countries and also in North America. “Fungi of Temperate Europe” describes it as being widespread and rather common.

This is the current distribution in the British Isles:

Distribution map for Zythia resinae from The British Mycological Society Fungal Records Database of Britain and Ireland. [Accessed on 28th December 2025].

(My record will be submitted to the FRDBI database in 2026, so does not appear on the map above.)

Zythia resinae is small and easily overlooked but lack of a suitable habitat (conifers with patches of resin) probably means it is genuinely scarce in parts of the country with mostly deciduous trees, such as East Anglia. Many woods (especially in Norfolk) are privately owned and lack public access, and this must surely be a factor as well.

The Dark Side

Zythia resinae’s relative, Sarea difformis, also grows on conifer resin. It consists of black discs and was once thought to be a lichen. A black fungus growing on black conifer resin is difficult to see, so it is even easier to overlook than Zythia resinae.

Sarea difformis is illustrated on page 1445 of Volume 2 of Laessoe and Petersen’s two volume “Fungi of Temperate Europe”, where it is described as “widespread, probably common but easily overlooked”. As with Zythia resinae, there are scattered records throughout much of the British Isles, but not from East Anglia.

Its worldwide distribution is similar to that of Zythia resinae, with the addition of a handful of records from Asia.

Gary Walton, who lives in Minnesota in the northern United States, writes about it on his October 2025 blog post “Sarea difformis: A fungus that lives on conifer resin“.

I will keep a lookout for Sarea difformis in Norfolk – now I know that it exists.

Resin eaters?

Zythia resinae and Sarea difformis are known as resinicolous, as they grow on resin from pines and other conifers. They have ancestors that date back to the late Jurassic or Cretaceous periods (about 140 million years ago), around the time that pine trees (genus Pinus) were diversifying (note 1).

Conifers (particularly those in the families Araucariaceae, Pinaceae and Cupressaceae) produce resin in response to damage. This seals wounds, protects against herbivores and inhibits the growth of microbes. Resin is runny when first produced (about the same viscosity as honey) but it soon solidifies. Resin forms a physical barrier to penetration by fungal hyphae, especially when hardened but when it still liquid it can flow around fungal hyphae and spores, trapping them. It also protects chemically, as it contains terpenoids with anti-fungal and anti-bacterial properties. It is a pretty specialised habitat for anything to grow on (note 3).

Zythia resinae‘s specific name resinae comes from the Latin word resina which means “resin” and genus name Zythea is derived from the Greek zythos meaning beer or ale. On the Mushroom Monday substack, Aubrey Carter wonders whether this refers to the idea that the fungus is fermenting some sugar in the resin.

There is still a lot to learn about the physiology and ecology of Zythia resinae and Sarea difformis.

For Zythia resinae, Aubrey Carter says “little is known about how the fungus lives. So little that we’re uncertain where the fungus obtains nutrients — perhaps the mycelium goes inside the tree, perhaps they derive nutrition from the resin itself, or perhaps it’s a different mechanism entirely.”

And for Sarea difformis, Gary Walton says “I have looked for research papers on how Sarea can live on conifer resin, but the results have not yielded much information. Does it actually break down the resin components into simple carbohydrates? If so, then does it do this on its own, or is there a symbiotic relationship with bacteria or another fungus? Are the fungal hyphae growing in the resin or merely on top? How does it disperse? A lot of questions, and I’m sure there are answers somewhere.“

In his 1941 paper “Biatorella Resinae: The Perfect Stage of Zythia Resinae” Theodore Ayers describes how inoculation tests with artificial cultures of Zythia resinae on Pinus strobus failed to show that it was parasitic on the conifer. Since then, many researchers have tried to determine whether whether Sarea and Zythia are parasites, but the conclusions have been contradictory. Mitchell et. al. sum it up: “The varying results and generality of these tests leave unresolved the question of pathogenicity of species in Sareomycetes; some authors assume pathogenicity and others accept a saprobic lifestyle” (note 1).

The conifer stump where I found Zythia resinae was most definitely dead, so presumably the fungi were living saprobically. But the tree must have produced its resin when it was alive and presumably very poorly. When did Zythia resinae colonise the resin? I will never know.

Notes

Note 1 – Mitchell JK, Garrido-Benavent I, Quijada L, Pfister DH (2021). “Sareomycetes: more diverse than meets the eye.” IMA Fungus Vol 12, article 6. The paper is freely available to download at https://link.springer.com/article/10.1186/s43008-021-00056-0. Sarea difformis s.lat. was split into Sarea difformis s.str. and Sarea coeloplata. A new genus was also formed, Atrozythia. Most importantly for us, Sarea resinae s.lat. became Zythia resinae, a single though genetically and morphologically variable species.

Note 2 – These synonyms are listed in the Species Details for Zythia resinae on the British Mycological Society’s Fungal Records Database of Britain and Ireland website. A login is required to access the information, which includes the distribution map shown above, as well as a facility for exploring individual records. New users can register to use the website free at https://www.frdbi.org.uk/user/register.

Note 3 – Resins are solid or highly viscous liquids that can be converted into a polymer. Amber is fossilised tree resin. It sometimes contains insects that were trapped in liquid amber and preserved as it solidified.

Golden Conecap, Conocybe aurea

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This August I found some rather striking small, bright yellow-orange fungi in pots of compost. They were Golden Conecaps, Conocybe aurea.

Golden Conecap, Conocybe aurea

Golden Conecap, Conocybe aurea

Golden Conecap on the Allotment

My allotment neighbours Karin and Simon grow some fantastic fruit and vegetables and in summer their greenhouses are full of healthy and productive tomatoes, cucumbers and peppers. I sometimes water their plants when they’re away, and they do the same for me.

On 6th August 2025 I was watering some of their pots when I noticed some rather pretty fungi growing in the compost. I didn’t have my camera with me, so I picked a couple of them and brought them home for a closer look.

I was reasonably sure they were a species of Conocybe (conecaps), a genus of saprotrophic fungi that grow on soil, dung, compost heaps, herbaceous litter or woody debris. Funga Nordica has a key to 62 species found in Northern Europe and Geoffrey Kibby illustrates 30 of them (note 1).

Species of Conocybe are not very easy to identify but I was pleased to see an illustration of a brightly coloured species that might be a match for my find, Conocybe aurea, in Volume 4 of Geoffrey Kibby’s “Mushrooms and Toadstools of Britain and Europe”.

Golden Conecap, Conocybe aurea

Golden Conecap, Conocybe aurea

I did some microscopy and checked the spores and cheilocystidia (cells on the gill edges) and caulocystidia (cells on the stem of the fungus). Everything fitted Conocybe aurea.

Spores of Golden Conecap, Conocybe aurea.

Spores of Golden Conecap, Conocybe aurea. (In water, x1000.)

Golden Conecap, Conocybe aurea

Cheilocystidia of Golden Conecap, Conocybe aurea (stained in Congo red, x1000). The caulocystidia (cells on the stem of the fungus) are the same shape.

I wanted photographs of the fungi in situ but I was out the next day and when I visited the allotment on 8th August, armed with a camera, there was no sign of any.

Luckily the original fruitbodies kept well in the fridge and I took them along to the Norfolk Fungus Study Group AGM the following day and showed them to Tony Leech, the Norfolk County Recorder for fungi. He had seen the species before, in September 2023 when his friend Donna found them growing in compost around a newly planted grape vine in her garden at Melton Constable. That was the first record of Conocybe aurea in Norfolk. He agreed with my identification (note 2).

More fruitbodies appeared during August and the first half of September and I managed to take pictures of Golden Conecaps at various stages of growth in several different pots, growing with cucumber, mint and basil plants in a commercial peat free compost.

Golden Conecap, Conocybe aurea

Golden Conecap, Conocybe aurea, mid August 2025.

Golden Conecap in the British Isles

Conocybe aurea is a rather scarce fungus in the British Isles and just ten records are listed on FRDBI (the Fungal Records Database of the British Isles) at the time of writing. (My record should reach the database next year.)

Not everyone records fungi, even when they’ve identified them, and although Conocybe aurea is very pretty I suspect its identification is often dismissed as being too difficult. (And it doesn’t feature in many illustrated guides to fungi.)

Here is the distribution map for Conocybe aurea in the British Isles:

Distribution map for Conocybe aurea from The British Mycological Society Fungal Records Database of Britain and Ireland. [Accessed on 15th November 2025]

Distribution map for Conocybe aurea from The British Mycological Society Fungal Records Database of Britain and Ireland. [Accessed on 15th November 2025]

The earliest records on FRDBI are from September 2010, when Andy Overall found Conocybe aurea on Hampstead Heath in London.

In 2014, he co-wrote an article with Vivien Hodge in Field Mycology entitled “Conocybe aurea, a rare British native or another coloniser?” (note 3) and described how he “spotted some bright yellow fungi fruiting inside a large clay pot, which was being used for growing herbs in a rich compost”.

The article concludes that Conocybe aurea “is recorded from soils rich in nitrate, fertilised meadows, old compost, bark mulch and in greenhouses, as well as freshly sown lawns. Whether this is a genuinely rare British species or an occasional coloniser from elsewhere is not known at present. Any further information that clarifies the origin and status of the species would be of great interest to the authors.”

The story starts earlier than 2010, as Overall & Hodge note that Conocybe aurea was recorded at South Queensferry in Scotland in September 1969 and this led to the species being listed as British (note 4).

Funga Nordica describes the habitat of Conocybe aurea as “on nitrogen rich soil, dung, sawdust, bark litter and fertilized meadows”.

The ten records on FRDBI list the substrate as “soil” (seven records) and “compost” (three records) and the associations are given as “grass” (three records), “Tulip (Tulipa)” and “Spruce (Picea)” (one record each).

Andy Overall included Conocybe aurea in his book “Fungi: Mushrooms & Toadstools of parks, gardens, heaths and woodlands” (2017), which illustrates over 750 species of fungi with beautiful photographs. He describes the habitat as “On nitrogenous soil but also amongst woodchip mulch, in gardens, parkland, cemeteries or open woodland”. He notes that Conocybe aurea isn’t edible (note 6).

Further Afield

Records of Conocybe aurea on the Global Biodiversity Information Facility (GBIF) mainly come from Europe and North America, but the fungus has been found in South America, Australia and some parts of Asia.

At the time of writing, the United States has most records (163), followed by the Netherlands (85 records) and Switzerland (51). Germany and Denmark are next, followed by the United Kingdom. September and October are the most likely months to find Conocybe aurea.

Golden Conecap, Conocybe aurea

Golden Conecap, Conocybe aurea. The same specimens as in the last photograph, but a couple of days older.

I do hope I find Conocybe aurea again. But even if I don’t, I feel lucky to have found such these beautiful fungi so close to home.

It was more than enough reward for watering some pots.

Notes

Note 1 – “Funga Nordica: Agaricoid, Boletoid, Clavarioid, Cyphelloid and Gastroid Genera” (2008), edited by Henning Knudsen and Jan Vesterholt (Nordsvamp, Copenhagen). A fantastically detailed book with keys and line drawings of spores, cystidia etc. Sadly out of print but available to download as a PDF.

“Mushrooms and Toadstools of Britain & Europe – Volume 4” (2023), by Geoffrey Kibby. Part of a four volume set of books, beautifully illustrated by the author. Still in print.

Note 2 – Tony Leech wrote about this first for Norfolk in “Wildlife Report 2023: Fungi” in Transactions of the Norfolk & Norwich Naturalists’ Society Volume 57, Part 1 (2024).

In October 2023 Geoffrey Kibby posted a lovely picture of Conocybe aurea growing in a post of Cosmos on the British Mycological Society (BMS) Facebook page. I think this is the second record for Norfolk, which would make mine the third.

Note 3 – Field Mycology. Volume 16, Issue 1, January 2015, Pages 14-15.

Note 4 – Watling, R. (1982). British Fungus Flora Vol. 3: Bolbitiaceae. Edinburgh, HMSO. The fungus was growing on a track in woodland by the estuary of the River Forth. The fungus was “distinctive in its beautiful colours… saffron to apricot”. The species was first described by the mycologist Julius Schäffer in 1930 as Galera aurea and renamed Conocybe aurea in 1962 (note 5).

Note 5 – Julius Schäffer (3rd June 1882 – 21st October 1944) was an eminent German mycologist.

Schäffer enjoyed eating Brown Rollrim fungi (Paxillus involutus) at a time when they were considered to be a good edible mushroom. However, in early October 1944 he and his wife ate a meal containing Brown Rollrims and after about an hour he developed vomiting, diarrhoea, and fever. He was admitted to hospital the following day and died of renal failure just over a fortnight later.

It is now known that Paxillus involutus contains an antigen that can eventually (often after consuming the fungus many times over many years) trigger an autoimmune reaction causing the body’s immune cells to attack its own red blood cells.

Modern books on fungi describe Brown Rollrims as “not edible – toxic” but the real danger of eating them has only been understood for the last forty years. Earlier field guides “Collins Guide to Mushrooms & Toadstools” by such as Lange & Hora (1963, but reprinted into the 1980s) say “harmless if cooked, of little value; slightly poisonous to some when raw”.

Wikipedia cheerfully notes: “Despite the poisonings, Paxillus involutus is still consumed in parts of Poland, Russia, and Ukraine, where people die from it every year.”

Note 6 – Sadly, Andy Overall’s book is now out of print but I managed to find a secondhand copy earlier this year. It is too heavy to take out into the field but it has some of the best photographs I’ve seen of a range of fungi found in the London area (but also further afield), accompanied by some very useful text.

Five Fungi from Sweet Briar Marshes

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Sweet Briar Marshes

Sweet Briar Marshes is a 90 acre Norfolk Wildlife Trust nature reserve in Norwich, purchased in 2022 after a public appeal and officially opened in spring 2024.

The reserve is crossed by Sweetbriar Road, part of Norwich’s busy outer ring road, with a third of the land area on the east side, nearer the city centre, and the other two thirds to the west. The eastern portion includes a Site of Special Scientific Interest (SSSI). Much of the western part of the reserve was arable farmland until as recently as the 1990s.

The reserve has contrasting wet and dry areas. The wet areas, nearer the River Wensum, consist of fen and grazing marsh with wet woodland and slightly higher wooded islands.

Sweet Briar Marshes, October 2025

Wooded island and fen, Sweet Briar Marshes, October 2025

The dry higher ground is mainly rough meadows with scattered hawthorn and broom bushes, with old hedgerows and younger woodland.

One of the main paths at Sweet Briar Marshes.

One of the main paths at Sweet Briar Marshes, August 2025. The surface allows access for wheelchair users and the raised curb (seen on the right) was installed to provide a landmark for partially sighted visitors.

There are some lovely veteran oaks and woodland pools which can be full of water or completely dry, depending on how much rain has fallen.

In a wet winter (such as 2023 – 24) the wet areas are very, very wet, drainage dykes are impassable and the river floods onto the lower lying parts of the reserve, but at the time of writing the whole reserve is very dry and the woodland pools are empty of water.

Fen in summer (August 2024)

Fen in August 2024, with flowers of Water Mint & Common Fleabane.

As a member of Norfolk and Norwich Naturalists Society (NNNS) I’ve been able to visit areas of the reserve not normally accessible to the public, as part of a two year project to record wildlife, plants and fungi on the reserve. My wife Vanna and I also lead guided walks on the reserve, Vanna looking at insects and other invertebrates, while I lead fungal forays.

Recording Fungi at Sweet Briar Marshes

I started to look at Sweet Briar Marshes fungi in 2023. Norfolk Fungus Study Group has visited twice and other records have been submitted by individuals, including members of the British Mycological Society (BMS), who visited as part of their spring field meeting in March 2025.

Norfolk Fungus Study Group visit to Sweet Briar Marshes October 2024

Norfolk Fungus Study Group’s visit to Sweet Briar Marshes October 2024. Cows graze the reserve and there are a couple of fresh cowpats in the photograph at the bottom left.

The current official tally is 275 species of fungi, but we’ve added quite a few species since then, so the true number must have easily reached 300 species.

Five Fungi from Sweet Briar Marshes

Here are accounts of five of the fungi I’ve found at Sweet Briar Marshes.

They’re not always the prettiest but, with the exception of Birch Knight, they were all new species for me, and sometimes for Norfolk.

1. Birch Knight, Tricholoma fulvum

The Birch Knight, Tricholoma fulvum, isn’t a rare fungus and is described as “very common and widespread throughout Britain and Ireland“. But the woodland needs to be wet and you need to visit its habitat at the right time to be lucky enough to see it.

I’d only seen it once before, at Broadland Country Park in November 2021, so I was very pleased to encounter it on this Tuesday’s public foray at Sweet Briar Marshes. It was growing beneath a Silver Birch tree on one of the small wooded islands, a new species for the reserve.

Birch Knight, Tricholoma fulvum

Three picked fruitbodies of Birch Knight, Tricholoma fulvum.

Birch Knight, Tricholoma fulvum, in situ.

The fungus has a reddish-brown cap, often with radial brown streaks, and bright yellow, adnexed gills that become marked with brown spots as they age.

Three picked Birch Knight fruitbodies.

Three picked fruitbodies of Birch Knight, Tricholoma fulvum. Note the adnexed gills marked with brown spots.

Birch Knight forms an ectomycorrhizal relationship with birch trees, supplying the tree with water and minerals in exchange for sugars, which the tree manufactures by photosynthesis. Other partners include Beech (Fagus sylvatica) and oaks (Quercus) and firs (Abies) and spruces (Picea).

2. Hypholoma subericaeum

Hypholoma subericaeum

Fungi growing in the bottom of a dried up drainage dyke: Hypholoma subericaeum

On a visit to Sweet Briar Marshes last Saturday I found a mass of moderately sized fungi growing amongst plant remains at the bottom of a dried up drainage dyke. They were rather lovely, with perfect very round caps. They were clearly something I hadn’t seen before, so I picked them and took them home. I consulted several books, looked at some websites and did some microscopy and finally decided they were Hypholoma subericaeum. (There are similar species with larger spores.)

Hypholoma subericaeum

Three picked fruitbodies of Hypholoma subericaeum.

The fungus doesn’t have an English name but its German name, Teichrand-Schwefelkopf, translates as the very appropriate Pond-edge Sulphur Cap. Its habitat is described as “Saprobiotic on the banks of drying, stagnant waters on rich, putrid mud soils between pioneer plants and old herb roots.” There are seven previous records for Hypholoma subericaeum in Norfolk, on wet soil.

Hypholoma subericaeum is a relative of the much more familiar Sulphur Tuft, Hypholoma fasciculare, which is also saprotrophic. It grows on dead tree stumps and breaks down the wood to obtain its food.

Sulphur Tuft, Hypholoma fasciculare

Young Sulphur Tufts, Hypholoma fasciculare, on a mossy tree stump.

3. Lakeside Webcap, Cortinarius lacustris

In October 2024, on a fungal foray, Vanna and I spotted a group of fungi near the edge of one of the wooded islands on the marsh, under a  Pedunculate Oak (Quercus robur). On closer inspection they were a species of webcap (Cortinarius), a genus of  fungi that forms mycorrhizal relationships with trees.

Young fruitbodies of webcaps have a cap encased in a cobweb-like veil, a protective covering known as a cortina (note 1). Traces are left behind on the stem and cap of the fruitbody and their colour provides important clues to the identity of the fungus.

Identification of webcaps is very tricky, as there are lots of species, many of which look very similar. Thankfully, there is now a good field guide, “The genus Cortinarius in Britain” by Geoffrey Kibby and Mario Tortelli (2021) which makes the task possible, if not easy.

Lakeside Webcap, Cortinarius lacustris

Lakeside Webcap, Cortinarius lacustris

We were leading a public foray at the time so returned the following day to collect some fruitbodies for a DNA sample. I  keyed out the fungus in the Kibby and Tortelli book and provisionally identified it as the Lakeside Webcap, Cortinarius lacustris.

Cortinarius lacustris

Picked fruitbodies of Lakeside Webcap, Cortinarius lacustris. The young fruitbody on the left has a white veil. The smell was fainly earthy or raphanoid (like radishes).

I was very pleased when DNA analysis by the Norfolk Fungus Study Group’s DNA Team confirmed that my identification was correct (note 2). This was a new species for the county and, at the time of writing Sweet Briar Marshes is the only known Norfolk site for Lakeside Webcap, Cortinarius lacustris. The species is described as “widespread in Britain” in deciduous woods, so more likely to have been overlooked than be a genuine rarity.

4. Lemonbalm Webcap, Cortinarius pilatii 

A year earlier, in October 2023, we found a group of webcaps in another area of deciduous woodland on the reserve.

They had a very pleasant scent, of Pelargonium mixed with roses, which usefully narrowed them down to one of a small group of webcaps with this type of smell. I provisionally identified them as Lemonbalm Webcaps, Cortinarius pilatii. DNA analysis confirmed my identification.

Lemonbalm Webcaps, Cortinarius pilatii

A small group of Lemonbalm Webcaps, Cortinarius pilatii.

Cortinarius pilatii

Picked fruitbodies of Lemonbalm Webcap, Cortinarius pilatii.

I found the fungi in the same place last year and a week or two later at Broadland Country Park, north of Norwich. Geoffrey Kibby added another Norfolk record, from Litcham Common, in November 2024. Described as “widespread and rather common” they are probably in many woods, but overlooked.

5. Poplar Fieldcap, Cyclocybe cylindracea

On our October 2024 public foray we had a look at a fallen poplar tree on the reserve. We’d found Yellow Shield, Pluteus chrysophaeus and Flame Shield, Pluteus aurantiorugosus, there previously, two colourful saprotrophic wood decaying fungi.

This time something bigger was growing on the tree: Poplar Fieldcap, Cyclocybe cylindracea. It grows in clumps on dead or dying trunks or stumps of poplar (Populus) and willow (Salix) and also on hardwood woodchips.

Young Poplar Fieldcaps, Cyclocybe cylindracea

Young Poplar Fieldcaps, Cyclocybe cylindracea.

Older Poplar Fieldcaps,Cyclocybe cylindracea.

Older Poplar Fieldcaps, Cyclocybe cylindracea.

Poplar Fieldcaps have a distinctive ring on the stem, which is obvious in the two picked fruitbodies below:

Picked Poplar Fieldcap fruitbodies,Cyclocybe cylindracea.

Picked Poplar Fieldcap fruitbodies, Cyclocybe cylindracea.

I hadn’t seen Poplar Fieldcaps before, so I was very pleased to see them. They’ve been found at Whitlingham, near Norwich, but most recent records have been in the west of the county. More fruitbodies appeared on the same tree in August 2025, after some rain.

Cyclocybe cylindracea has been cultivated since the time of the early Greeks and Romans and it is a good edible species. I took home a couple of fruitbodies to confirm their identity and I later cooked, ate and enjoyed them. But fungi provide a valuable habitat so I did the right thing and left most of the fruitbodies in place (note 3).

Notes

Note 1 – A cortina on a Cortinarius gives the genus its name. It has nothing to do with the Ford Cortina, my parents’ first car, which was produced from 1962 to 1982 and named after the Italian ski resort Cortina d’Ampezzo, the site of the 1956 Winter Olympics.

Note 2 – I have submitted quite a few samples of Cortinarius and other difficult to identify fungi for DNA analysis. My provisional identifications often turn out to be wrong, though we’ve found some interesting new species for Norfolk. But the fungi I choose for DNA analysis are difficult – and that’s the reason to check.

Note 3 – Fungal fruitbodies provide a habitat for for a wide range of invertebrates, including mites, springtails, beetles and the larvae of flies.

One of my biggest surprises this year came when I was about to cut a gill of a fungus I’d brought home from the Norfolk Brecks to look at under the microscope. A black and red rove beetle, some 20mm (0.78 inches) long, suddenly appeared from between the gills and I don’t know who had the bigger shock!

It was Oxporus rufus, a species that lives in decaying fungi. They are omnivorous and sometimes hunt for small insects.

I returned the beetle to the wild a couple of days later, during which time it had cut the gills with its powerful jaws and made a chamber where it could hide.

Oxyporus rufus

Beautiful and distinctive rove beetle, Oxyporus rufus, emerging from the rotting remains of a fungus. I took this photo when I returned the beetle to the wild.