Cystopteris fragilis


Cystopteris: From the Greek kystis 'bag' and pteris 'wing' or 'fern', alluding to the sack-like covereing of the sori

Common Name(s)

brittle bladder fern


Cystopteris fragilis (L.) Bernh.



Flora Category

Vascular - Exotic

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



Cystopteris laciniata Colenso


Naturalised. New Zealand: North and South Islands (from Auckland south to Dunedin). Also Northern Hemisphere, South Africa and South America.


Locally common in suitable sites along stream sides, ditches on damp stone walls, in muddy ground under willows (Salix spp.), and in shaded sites in grassland, along track sides and on roadside banks. In some areas it can be a very common fern on damp basalt and concrete walls bordering streams, ditches and channels


Terrestrial or lithophytic, deciduous ferns. Rhizome short-creeping, scaly, scales thin, black, black-brown, glossy. Fronds tufted, crowded, 100-450 mm long. Stipes 50-150 mm long, scaly at base, glabrous above. Laminae 10-300 × 60-140 mm wide, yellow-green, ovate to narrowly ovate, membranous, very delicate, glabrous, with widely spaced pinnae. Primary pinnae 30-80 × 15-40 mm, ovate to deltoid, apices tapering. Secondary pinnae 10-20 × 5-10 mm, ovate to oblong, lower most deeply lobed and/or divided into tertiary pinnae, apices acute. Sori numerous, rounded, in one row either side of midrib set away from pinna margins, submarginal; indusium ovate, pale delicate, attached at broader end to a vein arching over sori.

Similar Taxa

Distinguished from Cystopteris tasmanica by the larger, more divided fronds and longer primary pinnae with tapering apices.


Not applicable - spore producing

Flower Colours

No Flowers


Not applicable - spore producing

Propagation Technique

Somewhat weedy. Prefers a damp, shaded site, planted in a deep, moist, lime-enriched soil. However, this fern is not particularly fussy about soil fertility, flourishing in a range of soil types provided the sites are seasonally damp and shaded.

Year Naturalised



N. Temperate, C. and S. America

Fact Sheet Prepared for NZPCN by: P.J. de Lange (18 January 2012). Description adapted from Brownsey & Smith-Dodsworth (2000). Family follows Rothfels et al. (2012).

References and further reading


Brownsey, P.J.; Smith-Dodsworth, J.C. 2000: New Zealand Ferns and Allied Plants. Auckland, David Bateman.

Rothfels, C.J.; Sundue, M.A.; Kuo, Li-Y.; Larsson, A.; Kato M.; Schuettpelz, E.; Pryer, K.M. 2012: A revised family-leve classification for eupolypod II ferns (Polypodiidae: Polypodiales). Taxon 61(3): 515-533.

This page last updated on 20 Oct 2012