The word porcini in Italian means piglet, and is known by other names such as cepe (French) and steinpilz (German). The mushroom can grow quite large of upto 12 inches in diameter. They have a redish brownish colouring, with a spongy underside and a sometimes sticky texture.
The Porcini is perfect for use in soups, with meats, in risottos, and is especially nice in pasta. They are expensive, though are well worth the cost if you are lucky enough to source them.