Cyclosorus interruptus

Many of New Zealand’s threatened ferns are found in warmer climates on landmasses north of New Zealand, with New Zealand representing their southern distribution limits. These species tend to be restricted to northern areas of the country and occupy coastal and geothermal sites. Other species are restricted to habitats such as wetlands, which have suffered drastic modification and loss, or are palatable to stock and feral animals.

Key Features

  • Similar to Christella but the fronds arise from long-creeping stems and are tough and leathery with chestnut stalks and leaflets of similar size. Occurs in patches with erect fronds up to 80 cm long.

Distribution and Habitat

  • Swampy, coastal sites from Kawhia and Tauranga northwards, and in heated swamps, and around hot pools and steam vents in the Rotorua/Taupo area.


  • Competition with exotic weeds.
  • Habitat loss and modification.

Management Opportunities and Methods

  • Survey for new locations
  • Protection of habitat:
    • Avoid hydrological changes to swamps and thermal wetlands containing Cyclosorus (e.g. drainage; flooding to create water supply for fire control)
    • Exclude cattle (trampling is damaging)
  • Control exotic weeds
  • Establish new populations of Cyclosorus in suitable sites within its range

Monitoring Options

  • Check existing populations annually
  • Report new locations to DOC

Further Information and Support

  • New Zealand Plant Conservation Network (NZPCN).
  • Weed management - Department of Conservation, Regional Councils.
  • References:
    • Brownsey, P.J. & Smith-Dodsworth, J.C. (2000). New Zealand Ferns and Allied Plants. David Bateman, Auckland.
    • Wilson, C.M. & Given, D.R. (1989). Threatened plants of New Zealand. DSIR Publishing, Wellington.