Tmesipteris tannensis is a fern ally endemic to New Zealand. It is usually epiphytic on trees and tree ferns, but is occasionally terrestrial. An example of occurrence of T. tannensis within a tiered phytocoenosis is in Central Westland of South Island, New Zealand. These forests are the most extensive continuous podocarp/broadleaf forests in New Zealand. The overstory includes miro, rimu and mountain totara. The mid-story includes tree ferns such as Cyathea smithii and Dicksonia squarrosa, whilst the lowest tier and epiphytic associates include Asplenium polyodon, Astelia solandri and Blechnum discolor along with T. tannensis.