Staghorn ferns can be found high in tall trees but not growing "in" the bark. What that means is stags don't need or use soil as do land plants.
They get their nutrition substantially from the air. Pretty amazing, eh? Stags are therefore in the same class as orchids, for example, which also mostly grow in trees with no soil.
Platycerium is a genus of ~ 18 fern species in the Polypod family, Polypodiaceae. Ferns in this genus are widely known as Staghorn or Elkhorn ferns due to their uniquely-shaped fronds. This genus is epiphytic and is native to tropical areas of South America, Africa, Southeast Asia, Australia and New Guinea1. (wikipedia)