Marsh clubrush, kukuraho, purua grass
Scirpus fluviatilis (Torr.) Gray; Scirpus maritimus var. fluviatilis Torr.; Scirpus perviridis Cook
Vascular – Native
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.
2n = c.110
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants. Authors: By Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley.
2012 | Not Threatened
Previous conservation statuses
2009 | Not Threatened
2004 | Not Threatened
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.
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
Bristly nuts are dispersed by water and possibly wind (Thorsen et al., 2009).
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.
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
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