St. Helena Olive
Long before it went extinct, the St. Helena olive was a tough plant to track down. To see one of these small trees with pale pink flowers, you had to travel all the way to the small island of Tristan da Cunha, St. Helena, a British territory in the South Atlantic Ocean about 1,200 miles (1,931 kilometers) off the coast of Angola. They sat atop the island's east central ridge of mountains and had become exceedingly rare even as early as the 19th century. At that time just 12 to 15 trees were known to exist on the ridge's highest point, Diana's Peak — so few, in fact, that people soon just figured it had disappeared completely. But there, on one of the mountain's precipitous cliffs, one hardy survivor was discovered in 1977. Was there still hope?
Sadly, no. The St. Helena olive just wasn't able to overcome the longstanding threat of deforestation, and the fact that they weren't able to self-fertilize didn't help their chances, either. Further complicating the tree's problems were pests and fungal infections that were sometimes carried by the seeds. That last wild St. Helena's olive died in 1994, and by December 2003 all those raised by humans had died as well [source: Cairns-Wicks].