It looks like an upside-down umbrella, or a giant mushroom. Dracaena cinnabari, the dragon's blood tree, grows only on the island of Socotra in the Arabian Sea.

Its dense, umbrella-shaped crown shades its roots and helps it catch moisture from mist and clouds in the dry mountains. Cut its bark, and it bleeds a deep red resin.

That resin — dragon's blood — has been traded for centuries and used as a dye, varnish, medicine and incense.

Socotra has been isolated for millions of years, and many of its plants and animals are found nowhere else. But the dragon's blood trees face threats from a drying climate, grazing goats and storms, and many populations have few young trees.