Walkers miss it. Not because it is rare. Because it grows low to the ground in dense undergrowth or hangs from tree trunks in damp forests. The drooping filmy fern forms delicate curtains of translucent fronds that tremble in the breeze. It reaches up to 30 centimetres in length, with thin membrane-like leaves that allow light to pass through. Irirangi. The Māori name refers to this common filmy fern. Early Māori likely encountered drooping filmy fern in damp forests though its small size meant it was probably less significant than larger edible ferns. Settlers found the fern less palatable but recognised its value as an indicator of forest health. Today the species serves as an indicator of humid forest conditions. Its presence signals intact canopy structure and suitable moisture levels. The species inhabits damp shaded areas in native forests throughout New Zealand. It prefers high humidity and shaded conditions, thriving where rainfall is consistent and airflow is limited. Fronds are delicate and translucent, coloured bright green. Spores are produced on the underside of fertile fronds in small round clusters called sori. These spores are released into the air, drifting on wind currents until they land on suitable bark or rock substrate. Diet consists of nutrients obtained through photosynthesis and absorption from rainwater and decaying leaf litter trapped in bark crevices. The fern does not consume organic matter directly but rather extracts minerals from water and debris. This epiphytic lifestyle allows it to thrive in nutrient-poor canopy environments where other plants cannot establish. Classified as Not Threatened, drooping filmy fern remains widespread throughout New Zealand. Populations are stable in suitable forest habitat. However the species is sensitive to habitat disturbance. When forests are logged or modified, populations decline rapidly. Its presence signals intact mycorrhizal networks and healthy forest ecosystems. Conservation efforts focus on protecting remaining native forests from logging and development to maintain these critical canopy habitats.