Neat story about a coffee plant, found on only one island in the Indian Ocean, thought to be extinct:
http://www.npr.org/templates/story/story.php?storyId=5307047
In 1877, a European visitor, passing through Rodrigues, made a drawing of it and that is the only image we had of this plant, because after that, goats and pigs began to multiply on Rodrigues, and the plant began to disappear. By mid-century, it was presumed to be extinct. Then in 1979, a biology teacher on Rodrigues handed out copies of that 1877 drawing to a group of 12-year-olds, and one of the boys raised his hand and said, “Please, sir, I’ve got one near my house.”
More information on Wikipedia:
http://en.wikipedia.org/wiki/Ramosmania_rodriguesii
And at the Kew Botantic Gardens: