The Collaborative International Dictionary of English v.0.48:

Tuckahoe \Tuck"a*hoe\, n. [North American Indian, bread.] (Bot.)
   A curious vegetable production of the Southern Atlantic
   United States, growing under ground like a truffle and often
   attaining immense size. The real nature is unknown. Called
   also Indian bread, and Indian loaf.
   [1913 Webster]