Common Earthball, Scleroderma citrinum

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A couple of weeks ago I wrote about the Giant Puffball, Calvatia gigantea. It is one of several species of puffball that are good to eat, though all of them are smaller than the Giant Puffball.

But there is a common species of fungus that is superficially similar, which you shouldn’t eat – the Common Earthball, Scleroderma citrinum.

Common EarthballWhen I say superficially similar, I mean that both puffballs and the Common Earthball are spherical and sit on the ground without gills, pores or a stem. The Common Earthball is much wartier than any puffballs, with a thick and tough skin, covered with coarse and irregular scales. The skin is initially white, cream or yellow but may turn ochre-brown or green as it ages. (Citrinum refers to the citrine yellow colour of the skin.)

If you cut a mature Common Earthball open you will see the dark purply brown mass of spores inside; on really young specimens these are off-white, soon turning marbled brown and white. Puffballs have a pure white mass of spores when they are suitable to eat. You can squeeze a puffball like a marshmallow but the Common Earthball is much tougher and its skin will crack if you press hard enough (Scleroderma means ‘hard skin’). Sniff a Common Earthball and you may detect a slight unpleasant smell of gas; true puffballs smell pleasantly “mushroomy”.

Common Earthball

According to the Nature’s Secret Larder website, unscrupulous restaurants have been known to remove thin slices from the dark centre of Common Earthballs, soak them in truffle oil and serve them as real truffles.

This is a bad thing, as the Common Earthball is poisonous, although not in the league of the highly poisonous fungi such as Death Cap. If you eat it you are likely to experience gastrointestinal distress. (Wikipedia says that a few very sensitive individuals may experience lacrimation, rhinitis and rhinorrhea, and conjunctivitis from exposure to its spores.) In the United States the fungus is called the Pigskin Poison Puffball, a rather apt name.

Common Earthballs are indeed common and can be seen in autumn and early winter, in woodlands, on heathland, on shaded earth banks and on woodland and forest tracks. (The photographs above were taken in Blean Woods in Kent but I first saw the fungus many years ago at Buxton Heath, north of Norwich.)

Common Earthballs and puffballs have been lumped together in the gasteromycete fungi (the stomach fungi), but Common Earthballs are actually more closely related to boletes than puffballs, in particular boletes of the genus Gyroporus. If you want to know more, the First Nature website is a good place to start. It has some excellent photographs.

Giant Puffball, Calvatia gigantea

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It has been a dry September, although that is not particularly unusual in Norfolk. But rain at the end of August and very early in September made this a good year for the Giant Puffball, Calvatia gigantea. This is one of my favourite fungi: easy to identify, good to eat and spectacular in size.

Giant Puffball

Giant Puffball – just fresh enough to eat

The Giant Puffball occurs in Europe and North America on roadsides, in nettle beds, in meadows and fields and in deciduous forests. It is relatively common in the UK but is rare in Lithuania, protected in parts of Poland and considered to be of conservation concern in Norway. The fungus’ spectacular fruitbody is usually found in late summer and early autumn. However, the hot and dry early summer of 2006 was followed by heavy rain in early August and this caused Giant Puffballs to appear in large quantities.

The Giant Puffball is a large white globe around the size of a football (or soccerball if you’re American). It has no stem or gills, but attaches at the base to a fine strand, which connects to its mycelium growing beneath the soil. The diameter is usually around 30cm (12 inches) but the biggest specimen recorded was 162cm in diameter (64 inches). It is an unmistakeable fungus – although John Wright (“Mushrooms”, River Cottage Handbook No. 1, Bloomsbury 2007) admits to clambering into a field to pick a white duck!

The Giant Puffball is basically a bag of spores. If you want to eat your specimen, cut it open to check that it is pure white inside its skin , which feels like kid leather. Older specimens start to turn yellow and then olive-brown as the spores inside mature. Eventually the skin splits open and the spore-bearing material inside (the gleba) takes on the texture of crumbling foam rubber and masses of spores are released every time the puffball is disturbed, perhaps 7 trillion per puffball.

Giant Puffball

Giant Puffball – too old to eat

Last year I collected a Giant Puffball while out on a cycle ride in North Norfolk. It looked fresh enough, but I didn’t cut it open until I reached home, at which point I discovered that the inside was a yellowy-brown colour. So I left it on our back lawn and throughout the winter I kicked it around to disperse the spores whenever I went out into the garden. Whether I’ll ever have my own crop of Giant Puffballs is debatable – they are said to be difficult to cultivate.

I’ve only ever cooked Giant Puffballs by dipping slices in egg and breadcrumbs and frying them. The pieces melt in the mouth and have a texture like the very best tofu. More elaborate recipes exist and one day I hope to try The Puffburger recipe in John Wright’s book.

Giant Puffball

Giant Puffball – young and delicious to eat

The Giant Puffball has been used in medicine. It was cut into strips and used as a styptic dressing for wounds. Young fruitbodies contain calvacin, which acts against tumours, but it is only present in minute amounts.

Smouldering pieces of Giant Puffballs and other fungi were sometimes used as a soporific by beekeepers to calm their bees and allow access to the hive.  Another use was as tinder – a means of carrying fire from one place to another in the days before the invention of matches.

The scientic name Calvatia means ‘bald head or skull’ and gigantea means ‘giant’ – so the Giant Puffball means ‘giant bald skull’. Perhaps that’s another reason why I feel an affinity with this fungus.

Persicaria polymorpha, White Fleeceflower

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Back in October 2012 in my post “In Praise of Persicaria” I wrote about a couple of my favourite herbaceous plants of late summer and early autumn: Persicaria affinis and Persicaria amplexicaule. Now I must add a third to my list of favourites: Persicaria polymorpha.

Persicaria polymorpha

Persicaria polymorpha in our back garden.

Persicaria polymorpha is a dramatic plant. Although it is as tall and statuesque as Japanese Knotweed, it is a well behaved plant and is generally reckoned not to have its relative’s invasive tendencies.

I was given my plant last June. It had been cut back and was just a root ball with some short shoots but I was given a photograph of the plant before it was cut back and I knew this was a plant I wanted to grow. The plant dies back in the winter and it wasn’t until late April or early May that sizeable shoots started to emerge. By the end of June the plant was around five feet (150 cm) tall and it started to flower in the middle of July. When mature, the plant should reach 6 feet (180 cm) tall, with a similar spread.

The flowers are a lovely white froth, hence the English name White Fleeceflower. The flowers fade to pinky bronze by September. It is far prettier than Japanese Knotweed.

I’m growing my specimen in the lawn in the semi-shade, as our soil is very light and I want the plant to have enough moisture. Finegardening.com reckons that the plant can tolerate some shade and drier conditions, though it prefers moist soil. In our garden, not many insects seem to like the flowers.

Persicaria polymorpha works well as a single specimen in a lawn or can be planted in a wild garden. If you have a large border it would be great at the back, perhaps with grasses such as Miscanthus, as a foil for shorter, colourful perennials. It doesn’t need staking but heavy rain will push the foliage down, increasing the plant’s spread, so allow for this. The plant can be divided in the spring.

If you’re in the United States, you may find the reviews on the Dave’s Garden website helpful.

Incidentally, I’m not the only person who loves Persicaria. Here is an excellent piece on the Ben’s Botanics blog.