Carex ventosa


Carex: Latin name for a species of sedge, now applied to the whole group.

Common Name(s)

Chatham Islands Forest Sedge

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 - Naturally Uncommon
2004 - Range Restricted


2012 - IE, RR
2009 - IE


Carex ventosa C.B.Clarke



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



Carex McClurgii Petrie


Endemic, Chatham Islands where it is known from Chatham (Rekohu), Pitt, Mangere, Little Mangere, South East, Star Keys and Rabbit Islands.


A widespread sedge of Chatham Island lowland forest. Not found in deep peat and mainly associated with dune forests, coastal forests and tall scrub.


Stout, rather leafy, shortly-rhizomatous, tussock forming sedge of forested places and well drained soils. Rhizomes erect, rather short, up to 20 mm wide; loosely covered in fibrous leaf-sheath remnants. Culms 0.45-1(-1.5) m x 1-2.5-4 mm, trigonous, mostly smooth though scabrid below inflorescence. Basal sheaths brown. Leaves = to or > culms, 5-11 mm wide, double-folded, pale green to light glaucous green, margins finely scabrid. Inflorescence 0.2-0.5-1 m long of 7-15 spikes, these either approximate or the lowermost 1-4 distant, occasionally compound, pedunculate; terminal 1-4 spikes male; remaining spikes female, rarely with a few male flowers near their apices, 20-45-60 x 6-8-10 mm. Glumes (excluding awn) < or = utricles, ovate, acute or truncate, membranous with numerous, distinct nerves, colourless (hyaline) except for red-brown striations, and occasional larger dark red-brown markings beside the green midrib; awn scabrid up to 2 mm long. Utricles 4.5-5 x 1.5-2 mm, subtrigonous, ellipsoid, distinctly nerved, light greenish brown, margins quite glabrous; beak narrow bifid, c. 1 mm long, crura slightly scabrid; stipe minute. Stigmas 3, Nut 2 mm long, dark brown, trigonous, oblong.

Similar Taxa

Of the three other wide-leaved carices on the Chathams (C. trifida Cav., C. ternaria Boott in Hook.f., and C. chathamica Petrie), C. ventosa is perhaps most likely to be confused in the field with C. trifida. Ecologically, C. trifida is a strictly coastal species frequenting seal haul outs and sea bird breeding grounds and roosts, however, in some sites it overlaps with C. ventosa, and in such situations rare hybrids have been recorded (these may generally be recognised by their near sterile condition). From C. ventosa, C. trifida differs in its usually much wider (6-20 mm) dark glaucous leaves, shorter, more sturdy culms and usually larger and broader spikelets (35-50 x 6-15 mm). The glumes of C. trifida are consistently emarginated rather than acute, ovate or truncate as in C. ventosa. Herbarium specimens of C. ventosa have been confused with the peat-bog dwelling C. chathamica. From that species C. ventosa differs by the near colourless (hyaline) rather than evenly light red-brown coloured glumes, which are of equal length rather than exceeding the length of the utricles. The utricles of C. ventosa are more distinctly nerved and beaked than those of C. chathamica.


September - January


October - May

Propagation Technique

Easily grown by divison of whole plants and from fresh seed. An attractive sedge ideal for semi-shaded to shaded situations under tall trees or around buildings. Some selection is warranted as some wild populations seen have particularly glaucous foliage.


A common, widespread island endemic. It is not threatened on the Chatham Islands.

Chromosome No.

2n = c.62-64

Endemic Taxon


Endemic Genus


Endemic Family


Life Cycle and Dispersal

Nuts surrounded by inflated utricles are dispersed by granivory and wind (Thorsen et al., 2009).


Fact Sheet prepared by P.J. de Lange (10 August 2006). Description adapted from Moore and Edgar (1970)

References and further reading

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

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 18 Jun 2015