Magic Mushrooms

Sui-nong loves thunder. "It makes the mushrooms so scared, they simply jump out of the ground," he jokes. Sui-nong spends each summer scaling 3,500-m ridges in China's Yunnan province searching for mushrooms of a very special sort: the matsutake , a fungus prized above all others by Japanese gourmets.

Matsutake can't be cultivated — attempts to do so have eluded the world's experts. And they're anything but easy to find, growing under beds of pine needles or on the roots of ancient fir trees. They have to be rooted out extremely carefully to avoid damage. Scrambling up a vertical ridge,...