Botanical name:

Hymenophyllum nephrophyllum (Trichomanes reniforme)

Common name(s):

kidney fern, konehu, kopakopa, raurenga

About:

A unique fern characterised by its undivided, kidney-shaped fronds, is commonly known as the kidney fern. The fronds, also referred to as laminae, exhibit a shiny, translucent green colour. This translucency arises from their thin structure, measuring only one cell thick in the sporeling stage, which increases to 3–4 cells as the plant matures. A notable trait of H. nephrophyllum is its ability to tightly curl during dry periods to minimise moisture loss, contributing to one of its Māori names, kopakopa (meaning to wrap or clasp). Upon the return of rain or improved conditions, the fern unfurls and regenerates.

Natural habitat:

Coastal to montane up to 780m. Usually in dense forest but also found on boulders, rock falls, cliff faces and in some shrub land, and early stage successional forest. Rarely in pine plantations.

Growing environment:

Shade & Coastal tolerant.

Endemic distribution:

New Zealand’s North Island and in northern, western, and southern regions of the South Island, as well as Stewart Island and the Chatham Islands. It is not recorded from the eastern side of the South Island.

Flowering: N/A Spore producing

Fruiting: N/A

Uses:

Riparian plantings & Forests

How to grow:

Difficult! The lifecycle of the fern could not occur without damp soil as its spores require a moist environment.