The New Zealand Plant Conservation Network

Species

Schoenus fluitans

Etymology

Schoenus: rush
fluitans: From the Greek fluito (floating)

Common Name(s)

Floating Schoenus

Current Conservation Status

2012 - At Risk - Naturally Uncommon

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 - Range Restricted

Qualifiers

2012 - RR, SO, Sp
2009 - PD, RR, SO, Sp

Authority

Schoenus fluitans Hook.f.

Family

Cyperaceae

Flora Category

Vascular - Native

Structural Class

Sedges

Synonyms

None

Distribution

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.

Habitat

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.

Features

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.

Similar Taxa

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.

Flowering

December

Fruiting

January - April

Propagation Technique

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.

Threats

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.

Chromosome No.

2n = 10

Endemic Taxon

No

Endemic Genus

No

Endemic Family

No

This page last updated on 19 Jan 2014