We are regularly contacted by people who think they have found truffles. While some people have successfully found them, many have actually found "truffle look-alikes", usually other types of fungi that have a passing resemblance to truffles. Truffles grow just beneath the ground surface near beech, hazel, oak, birch and other deciduous trees, most commonly on alkaline soils such as found on chalk or limestone. These truffle look-alikes should not be eaten, many will cause stomach upsets.
Earthballs look a little like a warty potato. They are found on acid soils (e.g. wooded heathlands). They vary in colour from light brown to brown and usually have a yellow tinge. If you cut a mature specimen in half, it will be made of a black powder (the spores). An immature one will be white inside. An Earthball will give a stomach upset if eaten. You can see more images / learn more about the Earthball here.
Cramp Balls or King Alfred’s Cakes
If what you have found is black (or pinkish-brown on younger ones) and:
- Growing on an Ash, Beech or other tree (above the ground)
- When cut in half shows concentric circles
it is probably a Cramp Ball or King Alfred's Cake - do not eat!
These are comparatively common and widespread in England associated with deciduous trees but can be found with conifers. Veined Choiromyces are often irregularly shaped and can protrude through the ground surface and get quite big. Found in areas with acid soils they prefer clay. Sometimes confused with The Italian White Truffle (Tuber magnatum), their texture, aroma and flavour are completely different. The skin is smooth and white to yellowish brown and the inner is closely marbled of the same colours as the skin but with white veins. The smell is strong, aromatic at first, becoming unpleasant with age.
They should not be eaten as they reputedly cause stomach upsets.
Of the many types of truffle-like fungi which are often mistaken for them, are those of the genus Melanogaster. This name is from the Latin words for "Black" and "Stomach"! Internally they are almost marbled but the consistency is of jelly, not solid like a true truffle. They do not have the characteristic aroma and value of truffles, although some have been used culinarily. None are known to be poisonous. Four or five species are known from the UK. The Bath Truffle was formerly eaten and sold in markets. One writer said in 1884 of the Stinking Slime Truffle "a single specimen in a room is so strong as to make it scarcely habitable” !!
If what you have found is on the roots of a tree it may be a plant gall. The most well known plant gall is the Oak Apple. Plant galls are abnormal growths of plant tissues, similar to benign tumors or warts in animals. They can be caused by various parasites, from viruses, fungi and bacteria, to other plants, insects and mites.