Bolboschoenus fluviatilis


Bolboschoenus: From Greek: bolbos (swelling or bulb) and schoinos (rush, reed), from the supposed difference from the genus Schoenus in having bulbous tubers
fluviatilis: From the Latin fluvius 'river', meaning growing near rivers

Common Name(s)

marsh clubrush, kukuraho, purua grass

Current Conservation Status

2012 - Not Threatened

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 - Not Threatened
2004 - Not Threatened


Bolboschoenus fluviatilis (Torr.) Soják



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



Scirpus fluviatilis (Torr.) Gray; Scirpus maritimus var. fluviatilis Torr.; Scirpus perviridis Cook




Coastal to lowland in saltmarshes and other poorly drained saline areas, also found along some freshwater rivers and lakes. Sometimes invades pasture abutting tidal streams and estuaries.


Summer-green, bulbous perennial forming mostly densely clumped patches. Rhizome 7-9 mm diameter, woody, long-creeping, very dark brown, apices terminated by globose, ligneous tubers. Culms 1.5-2.5 m tall, 6-15 mm diameter, triquetrous, striated, smooth except just below inflorescence where scabrid on angles; basal sheaths loose, membranous, septate, brown to fawn, up to 150 mm long. Leaves numerous, less than, equal to , or greater than culms, 500 x 7-11 mm, double-folded but flattened, grass-like, tapering, coriaceous, margins and midrib scabrid towards apices; sheaths long, closed, coriaceous. Inflorescence a terminal, compound, irregular umbel; rays 6-9, unequal, 20-100 mm long, bearing clusters of 1-6 spikelets, a sessile glomerule of spikelets at the base of the rays; involucral subtending bracts similar to leaves, greater than inflorescence, unequal, 150-250 x 3-6 mm, as many as, or 1-2 fewer than rays. Spikelets 10-25 mm long, ovoid, or cylindric, dull red-brown. Glumes membranous, pubescent, apices cleft or lacerate, with a scabrid, recurved awn. Hypogynous bristles 6, more or less equal to nut in length, persistent, red-brown, retrorsely scabrid. Stamens 3. Style-branches 3. Nut 3.0-4.0 x 1.5-2.0 mm, equilaterally 3-angled with acute dorsal angle, obovate, apiculate, pale cream, occasionally black and glossy.

Similar Taxa

Bolboschoenus fluviatilis is the tallest of the three New Zealand species, and the one most likely to be found in freshwater systems. It differs from B. caldwellii (Cook.) Soják and B. medianus (Cook) Soják by the taller stature, conspicuously umbellate inflorescence with long, through irregular, rays, and distinctly trigonous nuts. B. fluviatilis has 3 rather than the 2 or 2-3 style branches typical of the other two species.


October - January


December - May

Propagation Technique

Easily grown from fresh seed and rooted pieces. Will grow in almost any soil but prefers a sunny, damp soil. Ideal as a pond plant or for planting along tidal streams.


Not Threatened

Chromosome No.

2n = c.110

Endemic Taxon


Endemic Genus


Endemic Family


Life Cycle and Dispersal

Bristly nuts are dispersed by water and possibly wind (Thorsen et al., 2009).

Cultural Use/Importance

Some inland occurrences in the Hamilton Basin (Waikato) peat lakes suggest that the species was planted deliberately for food by Maori.


Description adapted from: Moore, L.B.; Edgar, E. 1970: Flora of New Zealand. Vol. II. Government Printer, Wellington.

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 2009 Vol. 11 No. 4 pp. 285-309

This page last updated on 4 Dec 2014