Cyclosorus interruptus


interruptus: Interrupted in some way

Common Name(s)

None known

Current Conservation Status

2012 - At Risk - Declining

Conservation status of New Zealand indigenous vascular plants, 2012
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2012 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2009 and replaces all previous NZTCS lists for vascular plants. Authors: Peter J. de Lange, Jeremy R. Rolfe, Paul D. Champion, Shannel P. Courtney, Peter B. Heenan, John W. Barkla, Ewen K. Cameron, David A. Norton and Rodney A. Hitchmough. File size: 792KB

Previous Conservation Status

2009 - At Risk - Declining
2004 - Gradual Decline


2012 - SO
2009 - SO


Cyclosorus interruptus (Willd.) H.Itô



Flora Category

Vascular - Native

NVS Species Code


The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.

Structural Class



Many including Pteris interrupta Willd., Thelypteris interrupta (Willd.) Iwatsuki, Nephrodium propinquum R.Br., Nephrodium inaequilaterum Colenso, Nephrodium unitum R.Br., Cyclosorus gongyloides (Schkuhr) Link; Dryopteris gongylodes var. glabra (Mett.) Domin; Dryopteris gongylodes sensu Cheeseman


Indigenous: North Island, from Te Paki to Kawhia Harbour, the Bay of Plenty (including Mayor Island), the Rotorua Lakes to Taupo and near East Cape. Also known from Australia and throughout the tropical and warm-temperate Pacific where it is not threatened.


A species of geothermal habitats, and frost-free, coastal and lowland wetlands, especially those dominated by raupo (Typha orientalis) and swamp millet grass (Isachne globosa).


A creeping fern with harsh, hairless, olive-green fronds to 800 mm long. Frond stalks are slender, up to 600 mm long by 5 mm wide, almost black at the base but becoming brownish. Frond leaflets (pinnae) occur in 9–15 pairs, the basal pair are larger and sickle-shaped with each successive pair becoming shorter. The spores are found in closely packed sori distributed nearer the midrib than the leaflet edge.

Similar Taxa

Could only be confused with Pneumatopteris pennigera with which it sometimes grows. However, this species has longer, narrower pale green, soft hairy fronds of even length and shape that wilt easily. Pneumatopteris pennigera also occupies different habitats, being found on stream-banks in kahikatea remnants, and on shaded limestone overhangs and cave entrances.


Spore bearing fronds may be found throughout the year

Flower Colours

No Flowers


Spore bearing fronds may be found throughout the year

Propagation Technique

Easily grown from division of whole plants. Can be grown from fresh spore. Frost tender, and does best in damp or waterlogged ground.


Drainage, land development and fern collectors.

Chromosome No.

2n = 72

Endemic Taxon


Endemic Genus


Endemic Family


Life Cycle and Dispersal

Minute spores are wind dispersed (Thorsen et al., 2009).

Where To Buy

Sold by a few specialist native plant nurseries. Not widely grown.



References and further reading

Thorsen, M. J.; Dickinson, K. J. M.; Seddon, P. J. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 11: 285-309

This page last updated on 19 Dec 2014