N. gardneri mushrooms grow at the base of young babassu palms in Brazil. A bland tan by day, the fungi emit an eerie green light by night. Michele P. Verderane/IP-USP hide caption

itoggle caption Michele P. Verderane/IP-USP

This grocery store packet of porcini mushrooms contained a surprise: three species of fungi never before named or described. Bryn Dentinger/Royal Botanical Gardens, Kew hide caption

itoggle caption Bryn Dentinger/Royal Botanical Gardens, Kew

Hank Shaw, author of Hunt, Gather, Cook, snaps the end off a mushroom in a Washington, D.C.-area park. When broken, the inside turns blue, identifying it as an inedible species of bolete. The Washington Post/Getty Images hide caption

itoggle caption The Washington Post/Getty Images

Richard Blais' Earth & Turf Burger, served at the Flip Burger Boutique in Atlanta, is 50 percent beef, 50 percent mushroom. Courtesy of Flip Burger Boutique hide caption

itoggle caption Courtesy of Flip Burger Boutique

Four hundred million pounds of mushrooms come from farms in Chester County, Pa. Eliza Barclay/NPR hide caption

itoggle caption Eliza Barclay/NPR