Tuber lyonii

Tuber lyonii, also known as the American brown truffle or the pecan truffle, is a species of truffle native to North America. The pecan truffle is so named because it is most commonly found in pecan orchards, in association with the pecan tree. However, the pecan is not its only symbiote. Formerly considered nothing more than a nuisance by pecan farmers, the pecan truffle has been gaining in popularity as an edible mushroom in recent years and can fetch over $160 per pound at market....read more on Wikipedia.