Phenacoleachia zealandica is found on southern beech trees and Phenacoleachia australis is found on Pleurophyllum species, daisy-like plants in the Asteraceae family.
The islands are home to a number of rare plants including a unique genus the Auckland Island Pleurophyllum, and the only subantarctic orchids, Nematoceras dienemum and Nematoceras sulcatum of Macquarie Island.