Ivy, Hedera helix

Happy New Year! Since we have a few days to go until Twelfth Night, there is time to shoehorn in a festive reference:

The holly and the ivy,
When they are both full grown,
Of all the trees that are in the wood,
The holly bears the crown.”

I do like Holly, Ilex aquifoilum, but I prefer Ivy, Hedera helix. And Ivy isn’t just for Christmas – it provides a year-round habitat and food source for wildlife.

Small Tortoiseshell on Ivy flowers

Small Tortoiseshell butterfly feeding on Ivy flowers

Ivy is an evergreen climber and is native to western, central and southern Europe but it has been introduced into Australia, New Zealand and the western United States. It is Britain’s only evergreen liana. It belongs to the family Araliaceae, a family of around 250 species found in the Americas, Eurasia, Africa, Australia, New Zealand, New Caledonia and Pacific islands. Other well-known members of the family include Ginseng, Panax quinquefolius, whose roots are used in herbal medicine, the British wild flower Marsh Pennywort, Hydrocotyle vulgaris (which was considered to be a member of the Umbelliferae when I did Botany), the widely grown ornamental shrub Fatsia japonica and the Rice-paper Plant, Tetrapanax papyrifer, which I wrote about in October 2013.

Six pages of Richard Mabey’s ‘Flora Britannica’ are devoted to Ivy. It has a rich folklore, some of which is documented by the Owlcation website. I like Ivy’s association with the sale of alcohol – in medieval times ivy-covered poles were used to advertise taverns. (This led to the expression “Good wine needs no bush“.) Goblets were sometimes made out of Ivy wood and Ivy berries were supposed to overcome the bad effects of alcohol, although trying this is not a good idea because the plant is mildly poisonous. The Plants For A Future website describes Ivy as a bitter aromatic herb with a nauseating taste, so possibly it is better to stick with that hangover.

Various other uses for Ivy include making a brown dye from the twigs, using the leaves to wash clothes or restore black fabrics and, under the supervision of a qualified practitioner, as a folk medicine. The last point is important, as Ivy leaves and berries contain a saponin known as hederagenin, which can cause breathing difficulties and coma if ingested in sufficient quantities. Ivy sap can also cause dermatitis with blistering and inflammation, possibly due to the presence of polyacetylene compounds.

Other English names for Ivy include Cat’s foot, Me Hoofe, Robin-run-in-the-edge, True Ivy and Tun-hoof. Our Ivy, Hedera helix, is not related to the American species known as Poison Ivy, Toxicodendron radicans (Eastern Poison Ivy) and the related Toxicodendron rydbergii (Western Poison Ivy).

As the tough stems of Ivy creep along the ground, they root into the soil at intervals and produce lovely deep green leaves with three to five lobes and contrasting pale veins. These are known as shade leaves and the plant produces them as it grows over the ground and then first starts to climb up trees or walls. This growth can be very dense and will smother out other plants which is why it is often planted in gardens as a groundcover plant and especially as it happily grows in dense shade and dry conditions on poor soils. There are many garden cultivars, with different leaf shapes and colours.

Ivy - shade leaves

Ivy – shade leaves

Once the Ivy has scrambled its way up a tree or building and is growing in full bright sunlight it will it produce what are known as sun leaves. These are a lighter shade of green with less prominent veins and are a pointed oval in shape. It is only when the plant has put on a good growth of these leaves that it will then produce its lovely delicate flowers. An interesting fact about Ivy is that if you cut a stem of sun leaves and root it, it will grow into a self supporting free standing Ivy Bush.

Ivy - sun leaves and berries

Ivy – sun leaves and berries

Ivy is a very divisive plant, loved by some but loathed by many – including some foresters and custodians of ruinous buildings. It has a reputation for strangling or smothering trees and is sometimes assumed to be parasitic, sucking the life out of its host tree. But this is untrue – Ivy makes all its own food through photosynthesis and has its own root system for drawing up water and nutrients from the soil.

Ivy uses trees and walls as a support to scramble up and it can eventually clothe an entire tree in an evergreen mantle. This can deprive the tree’s leaves of light and, on dry soils, Ivy’s roots will compete with the tree for available water. Eventually the lush growth of Ivy at the top of the tree can make it top-heavy and vulnerable in strong winds or heavy snow fall, when the extra weight can bring branches down or even topple the tree. Because of this, foresters will regularly hack through the thick stems of Ivy enveloping trees near their base, cutting out a foot or so and then leaving the whole lot on the tree to wither and die, leaving an unsightly mess.

Ivy on walls and buildings can sometimes do damage too, but it can also protect walls. As the Ivy scrambles up any structure, it clings to it with little rootlets coming off the main stems. When the rootlets find crevices in walls, the plant will then send out proper roots into the structure and as these grow they can split any cracks further open. Often the main problem with ivy on old walls is when you try and pull it off – it clings so tenaciously that you can end up pulling off bits of wall with it. Because of this, on many old ruins it is now left in place, indeed sometimes it is the Ivy that is actually holding the structure together and keeping it upright. In cemeteries Ivy will cover gravestones, making them unreadable and potentially damaging some memorials, so it is often removed before it puts on too much growth.

However, if Ivy is allowed to climb up a dead or moribund tree, it can extend its wildlife habitat value beyond the life of the tree. Dead and decaying trees are of supreme wildlife importance to a variety of rare and vulnerable creatures, from beetle and moth larvae to roosting bats and nesting birds. Unfortunately such trees often end up being felled as they can pose a threat to people and property when they eventually come down. There is also a tendency amongst some to constantly ‘tidy-up’ the countryside by removing ‘dangerous’ trees even in the middle of woods.

Provided Ivy is given the occasional trim, it is a very beneficial plant, as it forms a kind of high-rise hotel for wildlife. Being evergreen, it provides shelter for invertebrates all year round, nesting sites for birds in the spring and summer and food for much of the year.

On woodland floors and hedge banks, a thick covering of Ivy leaves will conceal the entrances to mice and vole holes as well as bumblebee nests. Higher up, on old walls, Wrens, Blackbirds, Robins, Thrushes and other birds will nest in its dense cover. Ivy’s dense evergreen foliage provides ideal places for hibernating insects to securely sit out the winter, including butterflies like the Small Tortoiseshell (pictured above), Brimstone and Comma, as well as hoverflies and ladybirds. In spring a big clump of Ivy in a sunny position is a good spot to to look for emerging hoverflies and ladybirds as they crawl out of the dense cover to warm themselves before flying off to forage.

Hole amongst Ivy

On woodland floors and hedge banks, a thick covering of Ivy leaves will conceal the entrances to mice and vole holes as well as bumblebee nests.

Ivy flowers in autumn are perhaps its greatest gift to wildlife. Ivy flowers are produced in small, dense umbels and are pale yellow-green in colour. They are produced in September and will carry on flowering through October and well into November. Ivy is one of our latest flowering native plants and is an extremely important source of nectar for honeybees, wasps, hoverflies and butterflies. The flowers have a distinctive scent – a heady smell of honey – and some beekeepers harvest Ivy flower honey from their hives. It has a very distinctive taste, which I personally find a bit too overpowering.

On a sunny autumn day Ivy flowers will be covered in honeybees, so much so that you can actually hear the hum of their wings. If you search amongst the honeybees you will hopefully find some hoverflies, usually Eristalis species (Drone Flies) which mimic the honeybee in coloration but also sometimes something a bit more exotic like Volucella zonaria, a very large migrant hoverfly that is a perfect hornet mimic.

Drone Fly on Ivy flowers

Drone Fly on Ivy flowers

Ivy flowers are also a magnet for wasps, including the males, with their long antennae. There were good numbers of wasps on Ivy flowers this autumn, but numbers have plummeted in the last few years. Although they can be a nuisance at picnics, wasps form a vital part of the web of life. They are important pollinators and pest controllers, collecting and killing numerous caterpillars, whitefly and other nuisances to the kitchen gardener.

Another beneficiary of Ivy’s rich nectar is the Red Admiral butterfly which can often be found feasting on the flowers. In milder winters the butterfly may well hibernate in the dense leaves but they can be killed off by heavy frosts and long cold spells.

Red Admiral butterfly

Red Admiral butterfly on Ivy flowers

Holly Blue butterflies lay their eggs on the infant buds of the Ivy, their caterpillars feeding on them as they develop. Once the flowers are pollinated, the small green berries start to swell, turning brown and then ripening a lovely deep blue-black. These will persist right through the winter, surviving frosts and snow. They are beloved of Wood Pigeons and are a saviour to Blackbirds and Thrushes as well as overwintering Blackcaps.

When I wrote about Sea Aster last month, I mentioned the Sea Aster Bee, Colletes halophilus. Since 2001 the related Ivy Bee, Colletes hederae, has been spreading northwards in the British Isles. It reached Norfolk in 2014 and by the end of last year it had reached North Yorkshire and Lancashire. It is a very distinctive species, emerging late in the summer ready to feed on Ivy flowers. We found it in several parts of North Norfolk in our week staying at Wells-next-the-Sea, and there is a large colony on the outskirts of Costessey, only a few miles away from home. It is likely to continue its spread in 2017, so keep a look out on Ivy flowers this autumn.

Ivy Bee, Colletes hederae, on Ivy flowers

Ivy Bee, Colletes hederae, on Ivy flowers

Some plants benefit directly from Ivy too. Ivy Broomrape, which I wrote about in June 2016, is a parasite that grows on Ivy.

Sea Aster, Aster tripolium (a.k.a. Tripolium pannonicum)

At the end of September we spent another week in Wells-next-the-Sea in North Norfolk, staying in a holiday cottage not very far from the quay. Our stay coincided with the last week of warm summer weather and we spent every day walking or cycling, looking at flowers and insects.

Our day trips took us past several areas of salt marsh. Here, the Sea Lavender had more or less finished flowering, but the Sea Aster was still in bloom.

Sea Aster, Aster tripolium

Sea Aster, Aster tripolium, at Brancaster, North Norfolk, growing with Shrubby Seablite and Sea Purslane.

Sea Aster, Aster tripolium (a.k.a. Tripolium pannonicum), is a short-lived perennial that grows on salt marshes, on muddy sea-banks, tidal river banks and in brackish ditches. In the west of the British Isles, where the coast is rockier, it can be found growing on exposed sea cliffs and among rocks. Because of its adaptability, Sea Aster can be found around most of the coast of the British Isles. It is a halophyte – a plant that will grow happily in soils or waters containing high concentrations of salt. Like Danish Scurvygrass, Sea Aster has recently colonised the edges of roads that have been treated with salt, although to a much lesser extent.

Sea Aster has semi-succulent, strap-like leaves and stems. The plant is a member of the Daisy Family, the Asteraceae. It flowers from July to October and each flower head is a composite flower, made up of many individual, tiny flowers known as florets.

There are two varieties of Sea Aster in the British Isles, separated by their flower structure. Flowers of Aster tripolium var. tripolium have a central group of yellow disc florets surrounded by pale mauve or white ray florets, while Aster tripolium var. discoideus lacks the ray florets. My photograph above shows the rayless (discoideus) variety, which predominates in many parts of East Anglia, though the rayed form (shown in my photo at the end of this post and also here and here) is the commoner form in much of the British Isles.

Outside the British Isles, Sea Aster grows around most of the coasts of Northern Europe, north to North Norway (where it is rare), in Finland and south to Portugal and the Mediterranean. It occurs as far east as Japan, but it is an endangered plant in the Tokyo area, threatened by coastal development, encroachment of saline habitats by reed, and inappropriate management of flood defences. Because of this, Professor Noboru Kuramoto from Meiji University in Japan is investigating the distribution and ecology of Sea Aster in Britain and Japan, with the assistance of The Essex Field Club.

Sea Aster is edible, though I haven’t tried it yet. The leaves can be cooked or pickled and the BBC Food website has a recipe for Pan-fried Salmon with Aster tripolium and Scallop Broth, which sounds good, as do Sea Aster Fish Bake and the even simpler Buttered Sea Aster, on the Eatweeds website. The Galloway Wild Foods website suggests pickling Sea Aster in slightly sweetened white wine vinegar with herbs, such as Coriander leaves, Wild Thyme and green (unripe) Alexanders seeds. If you live near the coast, it is possible to forage for Sea Aster. You may be able to grow the plant in your garden as well. In his book “Around The World In 80 Plants” Stephen Barstow relates how managed to grow Sea Aster in his garden in Norway, in bed of sand and also in a bucket of fresh water.

Sea Aster flowers are attractive to butterflies such as the Red Admiral. But they are particularly associated with the Sea Aster Mining Bee, Colletes halophilus. In the UK, this charismatic insect is restricted to the coast of Southern and Eastern England, from the Humber Estuary down to Dorset, with most colonies on the East Anglia coast and the Thames Estuary. The bee emerges in August when Sea Aster is in full flower and flies until the end of September.

Although we were at the end of the flight period, we were able to see several female Sea Aster Mining Bees and we followed them as they flew from one flower head to another, wrapping their bodies around the Sea Aster flowers as they gathered pollen. We were also lucky enough to find a nest site, with lots of individual nest holes in a bank. However, we were too late in the season to witness a mating ball, where a female bee emerges from its nest hole and is surrounded by a cluster of males.

Sea Aster Mining Bee, Colletes halophilus

Sea Aster Mining Bee, Colletes halophilus, on (rayless) Sea Aster

Rayed form of Sea Aster

Sea Aster Mining Bee, Colletes halophilus, and (rayed) Sea Aster

The Raised Bed Is Dead… Long Live The Raised Bed

We spent early November altering our front garden and replacing the big raised bed we built in October 2013 with a larger, lower flower bed. In just over a week we moved tens of plants and around thirteen tonnes of soil. It was hard work but we are pleased with the end result.

New Raised Bed

The new raised bed, 27th November 2016

We built the original raised bed on top of concrete, as we didn’t have the funds to break up the drive. In spite of this, the bed was a success and after a year the plants were thriving. After three years the plants growing in it, including an Olive tree, a Salvia ‘Hotlips’, a Broom, a Rosemary bush, Lavender, Mexican Fleabane (Erigeron karvinskianus) and a Giant Feather Grass (Stipa gigantea), had knitted together to form a small patch of Mediterranean scrub. When I watered in hot dry spells in the summer, the scented shrubs released delicious wafts of perfume and reminded me of holidays in Corsica, Majorca, Provence and Greece.

So why did we decide to replace the raised bed? There were several reasons, including:

  1. The bulbs I had planted in the raised bed didn’t do very well. The daffodils which looked so good in the first spring were soon crowded out by the growth of the shrubs and the  tulips, Anemone blanda and white Muscari didn’t have enough moisture to thrive.
  2. We wanted to water as little as possible. The new bed is lower and will allow plant roots to reach far down into the sub-soil to gather water and nutrients.
  3. The double red Midland Hawthorn trees on our road (Crataegus laevigata ‘Paul’s Scarlet’) are lovely but they are ninety years old and trees of similar age on nearby roads have been condemned by Norwich City Council and are in the process of being removed. We wanted to plant a medium sized tree in our front garden as an eventual replacement for the street trees at the front of our house, but the raised bed wasn’t deep enough to do this.
  4. We wanted more space. The raised bed had a wide slab path around its perimeter, which we wanted to replace with a bigger growing area.

Key to our plans was hiring a contractor to break up the concrete. In April 2016 I asked my friend Sue Bell, who is a garden designer, for a recommendation and she suggested Ian Cooper of IFC Landscapes Ltd. We arranged for the work to be done at the start of November, when the plants could be moved easily in a semi-dormant state and Ian would have time to do the job.

With a week to go until the work was done, we dug out the plants and moved them onto the patio in the back garden. The following day we moved at least five tonnes of soil from the raised bed to the front drive and dismantled the edges of the raised bed. We put the sleepers to one side and rescued the nail plates.

Ian ordered a skip to hold the broken up concrete, which arrived on the Monday. He and a workmate arrived the next day and broke up the concrete. They did a very neat job and lifted and cut the slabs so that most could be reused. By lunchtime they had finished and we loosened the sub-soil, put the sleepers back as an edging to the new bed and shovelled the raised bed soil back. We ordered another two and a half tonnes of soil to top up the new bed, using a mix of topsoil and compost from G. Nicholls of Oaks Farm, Great Plumstead (01603 720224).

On the Friday the soil was delivered onto the drive and we shovelled it into the new bed. In the late morning and afternoon we replanted, spacing plants further apart and using some of the slabs to make a stepping stone path through the middle of the bed.

In the following week we planted a large, bare-rooted Oriental Hawthorn tree, Crataegus laciniata (also known as C. orientalis). It will provide a similar effect to the double red Midland Hawthorns but will also have edible and ornamental fruits. The leaves should provide food for any Hawthorn-eating insects and some of these will provide food for the birds.

Other newcomers to the front garden include three plants I bought at Norfolk Plant Heritage‘s Hethersett Plant Fair in August: a Honey Bush (Melianthus major), with lovely glaucous foliage and a mouth-watering whiff of peanut butter when bruised, Coronilla valentina subsp. glauca ‘Citrina’, with scented lemon-yellow pea flowers from late winter to spring, and Angels’ Fishing Rods (Dierama igneum), with arching wands of reddish pink flowers in summer.

I’ve also planted some more bulbs (Tulipa saxatilis ‘Lilac Wonder’ and Crocus chrysanthus  ‘Blue Pearl’) for early spring colour. I couldn’t resist adding a couple of Giant Echiums (Echium pininana). I may need to cover them with fleece to protect them from frosts. I have some spare plants in an unheated greenhouse, along with some Geranium maderense plants that I raised from seed this summer (from Ventnor Botanic Garden). I will plant these out in spring.

Work in progress

Work in progress (5th November 2016): the old raised bed has been removed and the concrete is ready to break up.

The Raised Bed Is Dead… Long Live The Raised Bed.

Blackthorn, Prunus spinosa

The Blackthorn, or Sloe, Prunus spinosa, is one of my favourite wild shrubs. The plant produces masses of pretty white blossom in early spring and sloes, a key ingredient in Sloe Gin, in autumn.


Sloes, late October 2016

In a week’s time I am going along to a gin tasting organised by No Fear Gardening, a new Norwich-based urban gardening club. My role is to talk about some of the ingredients used to flavour gin, including sloes. So I thought I could combine some homework with another post on my blog.

Blackthorn, Prunus spinosa, is in the Rosaceae, the Rose family. The genus Prunus can be split into six subgenera and three of these include several important fruit trees. Subgenus Amygdalus contains Almonds (Prunus dulcis) and Peaches (Prunus persica); subgenus Cerasus contains Cherries (Prunus avium and Prunus cerasus ) and subgenus Prunus includes Blackthorn and domesticated Plum trees (Prunus domestica). Blackthorn is believed to be one of the parents of the domesticated Plum, P. domestica, the other being the Cherry Plum, Prunus cerasifera.

The genus also contains the poisonous European Cherry Laurel (Prunus laurocerasus – subgenus Laurocerasus), the North American Sand Cherry (Prunus pumila – subgenus Lithocerasus) and European Bird Cherry (Prunus padus – subgenus Padus).

The sub-genera are distinguished by characteristics such as the arrangement of axillary buds and flowers, and the shape of the fruit.

Blackthorn grows in much of the British Isles, in open woodlands, hedgerows, as scrub on commons and rough ground and on screes and cliff-slopes. Although it normally grows as a shrub, it will grow as tall as 2.5 to 4 metres and will sometimes form a small tree (to ten metres tall).

When it is given the chance Blackthorn will spread sideways and outwards by suckers and a bush can be as wide as it is tall and often much wider. Indeed, I’ve spent many days keeping Blackthorn in check where it borders grasslands such as Alderford Common near Norwich. Without any maintenance these places would become solid thickets of Blackthorn. As well as providing a day of fresh air and exercise, clearance work in the autumn would often provide a good haul of sloes from the cut branches.

After a long, dark winter, Blackthorn blossom in the hedgerows is very welcome. Here in Norfolk, Blackthorn usually blossoms in March or April but the exact time varies depending on how warm a spring we have. Spring weather is very variable and a cold spell will often coincide with the onset of Blackthorn blossom, giving rise to the phrase “Blackthorn winter“. Cherry Plum (Prunus cerasifera) flowers even earlier than Blackthorn, with equally spectacular flowers.

Blackthorn blossom

Blackthorn in blossom

Blackthorn’s specific name spinosa refers to its sharp spines (which Cherry Plum lacks). These are very sharp and my bike tyres have suffered a number of punctures from Blackthorn spines, when hedges have been flail-mown and cuttings have been scattered on the road. The spines, which can reach over two inches (five centimetres) long, are also a hazard for anyone picking sloes or cutting Blackthorn scrub or hedges and they can easily penetrate leather gloves and even tractor tyres. It is quite common for part of a spine to break off after it has penetrated the skin and this can lead to inflammation, which can be serious. J. J. Kelly documented a number of cases in the 1966 paper “Blackthorn Inflammation” (on the Bone and Joint website) and other examples are given by H. Sharma and A. D. Meredith in a 2004 paper. The Netmums website gives some advice for children injured by Blackthorn.

Kneeling on a Blackthorn spine is a particularly bad idea (but is easy to do). A Blackthorn spine lodged in a joint can lead to a severe inflammation known as Plant Thorn Arthritis, Plant Thorn Synovitis or Thorn Arthritis. (Blackthorn isn’t the only species that can cause this.)

On a more cheery note, Blackthorn is an important plant for wildlife. Its flowers provide nectar for insects that emerge early in the spring, such as Small Tortoiseshell, Peacock and Brimstone butterflies, bees and hoverflies. The spines help to protect birds which nest in the branches and Blackthorn thickets can provide good habitat for Nightingales. In many parts of Europe, Shrikes (such as the Great Grey Shrike, Lanius excubitor), nest in Blackthorn bushes and impale a larder of food items on the thorns, which gives rise to their alternative name, the Butcher Bird.

Blackthorn is the food plant of the Brown Hairstreak and Black Hairstreak butterflies. Both species are quite restricted in range in the British Isles and the Black Hairstreak in particular prefers dense stands of mature blackthorn. A number of moth caterpillars also feed on Blackthorn. The Clouded Silver (Lomographa temerata), Green-brindled Crescent (Allophyes oxyacanthae) and Dark Dagger (Acronicta tridens) will also feed on other shrubs, such as Hawthorn, but the Sloe Carpet (Aleucis distinctata) is restricted to Blackthorn.

Blackthorn is easy to grow, though it is susceptible to Silver Leaf Disease, caused by the fungus Chondrostereum purpureum. (See my post “Winter Fungi” from 2012 for pictures.)  In the countryside Blackthorn is normally cut in the winter, but where Silver Leaf is a problem, you should only prune in dry spells in summer. (This is usually advised for Prunus fruit trees, such as Plums, Cherries, Almonds and Peaches.) If you do grow Blackthorn, give it enough room to spread or be prepared to cut back its suckers.

You have to be brave to eat a raw sloe, the Blackthorn’s fruit, and if you do you will probably do it only once. Sloes are very astringent, though frost can reduce the astringency and the Plants for a Future website says “some people find they can enjoy it raw“. (Avoid the stones, as they may contain cyanide glycosides.) The leaves can be used as a tea subsitute and the flowers are edible. There are also several medicinal uses for the plant.

Blackthorn wood is very hard and is used for making walking sticks and clubs, such as the Irish shillelagh.

The best use of sloes is for making jellies, syrups, conserves or flavoured alcoholic drinks. Sloe Vodka is quite good but the best is Sloe Gin. This is good to drink after just three months, but improves with age and becomes smoother and richer the longer it is stored. To make sloe gin, put pricked, bashed or frozen sloes in a large jar or demijohn and add sugar and gin (a cheap brand will do). There are numerous recipes, including these by River Cottage’s John Wright and on the BBC Food website and Very Berry Handmade website.

There are some great photographs of Blackthorn on the internet, such as on the Sulgrave Village and Wildscreen Arkive websites.

Porcelain Fungus, Oudemansiella mucida

Porcelain Fungus, Oudemansiella mucida

Porcelain Fungus, Oudemansiella mucida. Photograph by Vanna Bartlett.

Autumn seemed to arrive suddenly this year. In the last week of September it was still summer, then temperatures became more seasonal and we had some rain at last. With autumn came fungi.

On Monday we walked through the woods at Felbrigg Hall in North Norfolk. This is where I saw my first Porcelain Fungus (Oudemansiella mucida) several years ago. It was high up in a Beech tree but nonetheless the shiny white fruit bodies were unmistakable (see some great photos here). This time, however, we were lucky enough to find the fungus on a Beech stump and we could admire it in all its shining, slimy glory.

Porcelain Fungus can be found throughout northern and central Europe (see UK distribution) and grows on dead or dying Beech trees, or on dying Beech branches. Autumn is the time of year to see it. Sometimes it is very plentiful and the fruit bodies can cover an entire tree.

Porcelain Fungus is very slimy and its specific name, mucida, refers to the layer of transparent mucus that covers the fungus’ cap. The genus Oudemansiella contains between 15 and 42 species, depending on which classification system is used, and is named after the Dutch mycologist Cornelius Anton Jan Abraham Oudemans (1825–1906). Other English names for Porcelain Fungus include Poached Egg Fungus and Slimy Beech Cap.

The fungus is edible, though I haven’t tried it yet. It has the advantage of not looking like anything else, but if you do decide to try it, remove the mucus first. John Wright (in the River Cottage Mushrooms Handbook, which I have recommended before) describes how he was converted to eating this fungus. The mucus should be washed off and tough stems removed and then the caps can be sauteed. Apparently the flavour is “surprisingly rich”. The Wild Food UK website says Porcelain Fungus has a “good mushroomy taste”.

Porcelain Fungus fights off competing fungi by producing fungicides called strobilurins. (The name comes from Strobilurus tenacellus, the Pinecone Cap, which is where the compounds were first isolated. The Pinecone Cap uses strobilurins to stop competing fungi from growing on the pine cones on which it grows.)

According to an article in Pest Management Science entitled ‘The strobilurin fungicides‘ (D. Bartlett et. al 2002), commercially produced strobilurins were first sold in 1996 and sales totalled approximately $620 million in 1999, representing over 10% of the global fungicide market.

In the UK, DEFRA produces a fact sheet on strobilurins, ‘Use of Strobilurin Fungicides on Cereals‘ and The American Phytopathological Society has produced ‘QoI (Strobilurin) Fungicides: Benefits and Risks‘ on its website, which explains how the fungicides are applied. Strobilurins work by blocking electron transport in mitochondria so that they can no longer produce energy. Since their introduction in agriculture, some fungi have become resistant to strobilurins, so they are now used more sparingly, often in conjunction with other chemicals. (See also ‘Resistance Management is Essential with Strobilurin Fungicides‘.)