Vascular – Native
2n = 10
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 | At Risk – Naturally Uncommon | Qualifiers: RR, SO, Sp
Previous conservation statuses
2009 | At Risk – Declining | Qualifiers: PD, RR, SO, Sp
2004 | Range Restricted
Indigenous. In New Zealand known from the North Island where it is only found in the Central Volcanic Plateau (from the southern Kaingaroa Plain south) and the Ruahine Ranges. In January 2006 it was discovered on Chatham (Rekohu) Island. Common in Australia.
Mainly upper montane to subalpine (800-1500 m a.s.l.) bogs, tarns, slow flowing streams, muddy ground in and around seasonal pools, and on shallow lake margins. On the Chatham Islands S. fluitans has been gathered from restaid peat bogs in shallow pools amongst Sporadanthus traversii (F.Muell.) F.Muell.
Densely tufted or floating, usually dark red sedge of shallow pools, slowly flowing streams or muddy ground left by receding waters. Culms up to 600 x 0.5 mm, rooted at base, in terrestrial forms rooting freely at leaf nodes, otherwise rest of culm floating. Leaves 20-100 mm long, dark red or green, in floating forms distant, otherwise rather tufted, filiform, flaccid in aquatic plants, more rigid in terrestrial plants; margins slightly scabrid toward leaf apices; sheath very long, green or red-brown, margins membranous to chartaceous, prolonged toward apex as a ligule. Spikelets 2-4-flowered, in terrestrial forms often buried within leaves and scarcely distinguished, in floating forms more obvious; 7-12 mm long, narrow-linear, solitary, terminal, subtended by a glume-like bract, or rarely 2-3 spikelets distant at the end of the culm, the lower ones subtended by more leaf like bracts. Glumes 3-4, lanceolate, obtuse, membranous, light red or pale cream; all fertile or the lowermost empty. Hypogynous bristles 0. Stamens 3. Style-branches 3. Nut 2 x 1 mm, obovoid, brown with black patches or entirely black.
A very distinctive sedge which is unlikely to be confused with any other species. Plants may be confused with sterile plants of Juncus bulbosus, which now grows in similar habitats and can be coloured dark red. However that species has much finer, septate leaves. Within the New Zealand species Schoenus fluitans appears to be closely allied to S. maschalinus, and terrestrial plants of S. fluitans or those left stranded by receding waters in particular have some resemblance to it. However, S. maschalinus is a much smaller, more widely creeping plant (up to 1 m diameter) of lowland to montane wetlands and damp ground in forest. It is always coloured bright green (never red), is much more gracile, and has 6 hypogynous bristles (0 in S. fluitans), and a white rather than black or brown mottled black nut. Both species share the same chromosome number (2n = 10), and nrDNA ITS sequences place them as sister species.
January - April
Easily grown in a peaty soil within a partially submerged pot. Does best in semi-shade. However, it can be rather fickle and difficult to maintain for any length of time. In cultivation plants usually change colour for dark red to lime green.
A usually upland species which appears to be locally common over parts of the Central Volcanic Plateau. In some parts of this range it faces competition from Juncus bulbosus, and there is some evidence that it has become extinct in the northern part of its range due to that aggressive weed. The 2006 discovery on the Chatham Islands was accidental and its exact status there has yet to be determined.
fluitans: From the Greek fluito (floating)
Where To Buy
Not commercially available.
Fact sheet prepared for NZPCN by P.J. de Lange (August 2006). Description adapted from Moore & Edgar (1970).
References and further reading
Moore, L.B.; Edgar, E. 1970: Flora of New Zealand. Vol. II. Wellington, Government Printer
Please cite as: de Lange, P.J. (Year at time of access): Schoenus fluitans Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/schoenus-fluitans/ (Date website was queried)