it's called the winter truffle. Usually globular or not very pronounced lobate shape with black or dark purplish rind and very tightly-spaced warts, clearly evident with a depression at the summit and lengthwise grooves. The flesh is dark brown or blackish-grey with extensive white marbling. The spores are spinulate. Its size may exceed that of a hen's egg. It is found in the autumn and at the start of the winter under oaks and hazels. It is common throughout Central and Southern Europe. Its aroma and flavour are quite strong but pleasant.