Stinkhorn

Common names

• Common Stinkhorn
• Stinkhorn
• Witch's Egg

The common stinkhorn is a common type of mushroom, very easy to identify due to its unpleasant odour and the characteristic phallic shape, which led to many popular names in medieval England. Stinkhorn lives in both Europe and North America and consumes wood waste, found in large amounts in forests and gardens that are mulched. During the summer and late autumn, the fruiting bodies appear in such locations. Stinkhorn has a conical cap with a slimy surface and a dark olive color, while the stem is very long. The foul smell is designed to attract insects, since it resembles the one of a dead animal. The insects carry away the spores located on the conical surface, also known as a gleba. Young mushrooms are consumed in France and Germany, despite the bad smell that makes many people believe they are inedible. A French mycological pioneer with a peculiar sense of humour gave this widespread stinkhorn species the scientific name Phallus impudicus, due to its shape. All stinkhorns have the top of their caps covered by a slimy substance that smells terribly and contains spores. It acts as a magnet for flies, which will then carry spores away in their flights, contributing to propagation. Young stinkhorns have a white or pink color, with a typical size of 4 to 6 cm by 3 to 5 cm. Their shape resembles an egg, so they are known as the witch's egg. The young mushroom is protected by a white volva named the peridium in scientific terms, which can be quite thick. It covers the olive gleba, which has a gelatinous consistency. This part is responsible for the disgusting smell typical of the species. It actually consists of several parts: the outside green layer is the visible head of the mushroom, under it there is a hard white structure with a sponge-like texture, known as the receptaculum. The small "eggs" only need one or two days to become full-size mature stinkhorns. The mature examples are very tall, with a height between 10 and 30 cm. The conical top is no larger than 2 to 4 cm but hosts the green gleba, with its spores and slimy appearance. As the mushroom ages, the gelatinous layer eventually disappears and a yellow surface covered in ridges and pits is exposed. At this stage, it resembles Morchella esculenta, the popular common morel, and it is confused with it sometimes. It grows extremely fast and can expand by up to 10-15 cm every hour. Scientists estimate that fruiting bodies are strong enough to penetrate asphalt, generating a maximum pressure of 1.33 kPa. The tiny spores, between 3-5 and 1.5-2.5 �m, have an elliptical or oblong shape. Stinkhorn is sometimes confused with its relative P. hadriani in the forests of North America. However, P. hadriani has a different volva, with shades of purple. Stinkhorns tend to pop up unexpectedly on lawns or in gardens and have a striking effect and appearance. The transformation from the immature egg form is very quick; the species expands with vigour and breaks out of its shell. After only a few hours, the egg becomes a large tall mushroom, reaching a height of 25 cm or more. The species is not popular at all, for several reasons such as its foul odour. Similar to another mushroom, Scleroderma polyrhizum, it tends to grow in unwanted locations. Stinkhorn changes its look as it becomes older and can be confused with a yellow morel. Insects eventually clear all of the green slime from the cap and the uneven yellow surface that remains is similar to the one of a morel. Stinkhorns are also hollow and the smell disappears at this stage, so it's easy to see why the two mushrooms are misidentified. However, remnants of the slime always remain visible on the cap and stinkhorns don't grow during the summer like morels. It is a lot easier to confuse Phallus impudicus and Phallus hadriani. The only difference is the color of the volva, which is purple for the latter species.

Parts used

Fruiting body.

Culinary uses

The species is edible and can even be consumed raw, if parts of the inner receptaculum are sliced with a knife during the egg phase. Their taste is similar to the one of radishes, with a crunchy texture. In some areas of Germany and France it is a popular delicacy that can be consumed fresh or pickled, sometimes included in sausages. Stinkhorn is also eaten in China.

Habitat and cultivation

Stinkhorns are common all across Europe and North America but also grow in other parts of the world. They are found in India, China, Taiwan and locations as diverse as Iceland, Australia, Costa Rica or Tanzania. Stinkhorn inhabits the entire USA but is more common in the areas west of the Mississippi River. East of the river is the territory of another related species, Phallus ravenelii (popular name Ravenel's stinkhorn). It lives on decaying wood, so the fruiting bodies can be found during the summer and autumn in deciduous forests. Other habitats include parks, gardens and other areas covered by grass, as well as conifer woods. Stinkhorn can live in a mycorrhizal relation with a number of tree species. It is a saprobic species that grows both isolated and in large clusters. Stinkhorn is often encountered during the summer and fall in North America, in wood chips, cultivated areas, flowerbeds, meadows and lawns.