The Saint Helena Tree Fern (Dicksonia arborescens) is a characteristic plant of the "tree fern thicket" vegetation of the highest parts of the central ridge of the island of Saint Helena

Saint Helena

Saint Helena , named after St Helena of Constantinople, is an island of volcanic origin in the South Atlantic Ocean. It is part of the British overseas territory of Saint Helena, Ascension and Tristan da Cunha which also includes Ascension Island and the islands of Tristan da Cunha...

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It is important as a major component of a vegetation type that is one of the last remnants of the native vegetation. Many of the other endemic plants of this vegetation germinate as seedlings on the trunks of the tree fern, which thus acts as a nursery for the native flora.

The genus Dicksonia

Dicksonia

Dicksonia is a genus of tree ferns in the order Cyatheales. It is regarded as related to Cyathea, but is considered more primitive, dating back at least to the Jurassic and Cretaceous periods. The fossil record includes stems, pinnules, and spores....

contains several species widely dispersed around the world, including the New Zealand tree fern, Dicksonia squarrosa.