(With updates April 2020.)

At the end of September Vanna and I visited Holkham in North Norfolk to look for some of the specialist sand dune fungi that grow there.

Our friend Sarah, who took me to see Sticky Nightshade a few years ago, kindly gave us and our friend Ian a lift. When we arrived we met up with two of Sarah’s friends, Phil and Jane. Phil has a lovely photography blog, which now features some of the fungi we saw.

It has been a dry autumn so far in Norfolk and our first impression was that fungi were much less plentiful than at the same time last year. However, we managed to see an interesting selection, as well as a few flowers and insects. The soundtrack of the day was wind blowing the Marram Grass and the call of Pink-footed Geese – autumn had definitely arrived.

Here are some of the specialist sand dune fungi:

Dune Cup, Peziza ammophila

Our most impressive find was Dune Cup, Peziza ammophila. This cup fungus can be found amongst the sparse growth of Marram Grass (Ammophila arenaria) in consolidated areas of sand dunes. It develops underground and forms a deep cup- or urn-shaped structure, often mostly covered by sand. By blowing onto the cup, sand triggers the discharge of ripe spores, which are blown to new sites on the dunes. The fungus is a saphrophyte – it lives on dead and decaying organic matter. It is not considered to be edible.

Dune Cup, Peziza ammophila

Partly buried in the sand, the Dune Cup looks rather like a tiny moon crater and we half expected to see Clangers nearby. The Dutch name for the fungus is Zandtulpjes – “sand tulip”. The name ammophila means “lover of sand”.

Dune Cup is restricted to coastal sand dunes in Britain. Dune Cups occur in coastal dune systems in other parts of Europe and North America, though it is thought that “Peziza ammophila” is actually a species complex.

Dune Waxcap, Hygrocybe conicoides

I am a great fan of Waxcaps, a group of colourful fungi with a cool, waxen texture and often greasy or shiny caps, which I wrote about back in 2013.

Dune Waxcap, Hygrocybe conicoides, is a dune specialist, and grows in the grassier, more consolidated parts of dunes. Its name “conicoides” refers to its resemblance to Hygrocybe conica, the Blackening Waxcap, when young. However, the Dune Waxcap only blackens slightly, just on its stem, unlike H. conica.

Dune Waxcap, Hygrocybe conicoides

The Dune Waxcap can also be found in coastal areas of Scandinavia, Germany, Spain and the eastern United States and Canada. It is thought to have been introduced to Hawaii.

Tiny Earthstar, Geastrum minimum

The Tiny Earthstar, Geastrum minimum, is indeed very small. It is exquisite and also rather rare, restricted to sand dunes at Holkham in Norfolk and Sandscale Haws and Drigg in Cumbria, although it is reported to be widespread in Europe.

There are about a dozen species of Earthstars (Geastrum) in Britain, named because they have a central spore sac, surrounded by rays that project outwards, giving the appearance of a star. The spores are dispersed when a raindrop hits the spore sac, or when a breeze blows across it.

The Collared Earthstar, Geastrum triplex, our largest species, has rays that are 5 – 11cm across when open. In contrast, the rays on a Tiny Earthstar are just 1.5 – 3cm across.

Tiny Earthstar, Geastrum minimum

The Dwarf Earthstar, Geastrum schmidelii, is a similar size and is also found at Holkham. We saw some in 2017 but not this year. This guide from Kew Gardens includes a useful comparison of the two species. The most obvious difference is that the Dwarf Earthstar has a pleated pore opening.

Dwarf Earthstar, Geastrum schmidelii

Agaricus devoniensis

Agaricus devoniensis is another sand dune specialist, though it can occasionally be found on sandy soil away from the coast. Like other sand dune fungi, it survives in inhospitable surroundings by feeding on dead and decaying organic matter amongst the sand. It has whitish flesh but flushes pink when bruised. The smell is “mushroomy”.

Agaricus devoniensis is a relative of the cultivated mushroom, Agaricus bisporus. but I wouldn’t eat it because it is quite rare and also because “it is as edible as any nice meal topped with a liberal sprinkling of sand… you simply have to grit your teeth and get on with it“.

Dune Roundhead, Stropharia halophila

I thought the photograph below (taken on a previous trip to Holkham on 30th September 2017) was Agaricus devoniensis, but it turns out to be Dune Roundhead, Stropharia halophila.

I had no inkling of this until I was contacted in early April 2020 by Marco Contu from Sardinia. He has studied sand dune fungi for many years and he pointed out my error.  I checked with other members of Norfolk Fungus Study Group and they confirmed Marco’s identification.

Stropharia halophila (Originally misidentified as Agaricus devoniensis.)

It turns out that Stropharia halophila is a pretty rare fungus. It was described as a new species in 1988, from Southern Italy.

The NBN Atlas shows just one record for the UK, from Ainsdale in Lancashire, but the species has already been seen in Norfolk: Penny David (the wife of dune fungus expert Maurice Rotheroe) found it at Holkham in 1992 and her record was confirmed by Thomas Laessoe.

Stropharia halophila is being assessed for the Global Red List of fungi. It has been recorded “from very few, scattered and fragmented localities” in France, the British Isles, Italy and the Netherlands. The fungus is thought to be saprotrophic on the litter of Marram Grass, Ammophila arenaria.

Sand Stinkhorn, Phallus hadriani

We looked in vain for another sand dune specialist, Sand Stinkhorn, Phallus hadriani (also known as Dune Stinkhorn). This is a relative of the common and very smelly Stinkhorn, Phallus impudicus, which is found (and more often smelt) in woodland during the summer months.

Both species have the same phallic appearance, but Phallus hadriani is smaller and the “egg” from which the fruit body grows is pinkish-lilac, rather than white.

I’m used to the rotting flesh smell of the Stinkhorn so when I found a specimen of Sand Stinkhorn at Holkham last September I was pleasantly surprised by the much more delicate, slightly perfumed odour. Not everyone is as lucky – while I agree with the descriptions of the smell as “faint and pleasant” and “like violets”, some people think it is “fetid or putrid”. (More recently I have found some more mature specimens and they are a lot smellier, though not in the same league as Phallus impudicus.)

Sand Stinkhorn, Phallus hadriani

Outside the British Isles, Phallus hadriani has been introduced to Australia on woodchip and in North America it grows on decomposing tree stumps and roots.  In Poland it forms a symbiosis with xerophilous grasses and the Black Locust tree, Robinia pseudoacacia.

The specific name hadriani is named after the Dutch botanist Hadrianus Junius (1512–1575). Also known as Adriaen de Jonghe, he was the author of a 1564 pamphlet on Stinkhorn fungi.

(We returned to Holkham dunes in autumn 2019, when sand Stinkhorn was present in good numbers. Fungi are like that – every year is different, which is part of the joys of looking for them.)

The pinkish lilac egg of Sand Stinkhorn, Phallus hadriani

References

There is not that much information on the internet about these fungi, compared to some of the subjects I have written about, so I have relied heavily on the First Nature website for much of the information here. Other sources include Wikipedia and the excellent book “Collins Complete Guide to British Mushrooms & Toadstools” by Paul Sterry and Barry Hughes (Harper Collins 2009), where specialist sand dune fungi are described on page 340. Thanks to members of Norfolk Fungus Study Group and Marco Contu for their help with Stropharia halophila.