All good detective stories need a decent hunch, some intriguing clues and, these days, some sophisticated DNA analysis. If the plot revolves around an old, unsolved case, so much the better. The Tahitian vanilla mystery has all this and more: exotic locations and a trail that spans half the globe and at least half a millennium.

Tahiti is the home of the finest vanilla, but Tahitian vanilla has long been an enigma
For more than 50 years, botanists have puzzled over the origin of the vanilla orchid grown on the islands of French Polynesia in the Pacific Ocean. The first formal description of the species was based on a specimen from Raiatea, the second largest island in the archipelago and sacred to the Tahitians, so it was named Vanilla tahitensis. Yet the orchid was clearly alien to these islands.