The Santa Cruz Mountains, west of Silicon Valley, is the place, where many good mushrooms grow, including chanterelles, morels and porcini, that can cost up to $50 a pound at gourmet markets.

But there are also poisonous varieties with sinister names like "death cap" and "destroying angel" that can cause liver failure and death when eaten — and are frequently mistaken for their edible cousins.

"One mistake can be the difference between life and death," said Judith Alsop, director of the Sacramento division of the state poison control system. "If you're going to eat mushrooms, buy them from the store."

Such warnings do not scare off dedicated foragers like 43-year-old Thomas Keller, of Campbell. Serious hunters eat only what they can identify. Keller said once he learned to identify the distinctive color and sheen of death caps, he noticed them everywhere.

If the threat of a painful death weren't enough to scare off the amateur mycologist, mushroom foraging has been banned on many public lands, with fines as high as $1,000.

Red "no picking" signs in 10 languages have recently appeared at state and regional parks. California law prohibits the picking of mushrooms on state land without a special permit. And even then, there's a strict limit of five pounds per person.