The New Zealand Plant Conservation Network

Species

Carex ophiolithica

Etymology

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

Common Name(s)

North Cape 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

Qualifiers

2012 - OL
2009 - CD, ST, OL

Authority

Carex ophiolithica de Lange et Heenan

Family

Cyperaceae

Flora Category

Vascular - Native

NVS Species Code

CAROPH

Structural Class

Sedges

Synonyms

None

Distribution

Endemic. North Island, Te Paki, North Cape Scientific Reserve (serpentines zone only).

Habitat

A coastal species endemic to the 120 ha serpentinised zone of the North Cape Peninsule. Within this area it is a common species of open ultramafic scree, boulderfield, cliff faces and also under light scrub. It is also present on the plateau where it grows within the thick clay soils that have developed over the serpentinite.

Features

Stoutly erect, tufted bright green to green sedge of ultramafic substrates. Rhizomes short, ascending, slender, culms distinctly bulbous at base. Leaves 200-600(-800) x 1.8-3.2 mm, soft, ascending, double-folded, green to verdant-green; margins scabrid, weakly rasping (not harsh); keel on undersides weakly scabrid. Culms 150-920 x 0.5-1.2 mm, erect, glabrous in lower third, glabrous to weakly scabrid in upper two thirds, trigonous, shorter or longer than leaves when mature; basal sheaths to 20 mm long, pale brown to straw-coloured, nerves distinct. Inflorescence spikes 3-5, 10-40 x 3-4 mm, erect; upper spikes more or less approximate, lower 1(-2) spikes distant; peduncles 2-25 mm long; spikes subtended by narrow leaf-like bracts; these much longer than spike; terminal spike male, often with a few female florets in proximal part, female spikes slender, bearing 10-60 florets, florets overlapping but not crowded. Glumes 1.5-2 x 1.4-2 mm, shorter than utricles, glumes ovate, oblong, light green to pale brown, membranous, deciduous, with two lobes at apex, midrib light green to pale brown; awn 0.5-1.5 mm long, scabrid. Utricles 3-4 x 1.4-1.5 mm, narrow ovoid, elliptic, plano-convex or subtrigonous, pale green to live green when immature, usually pale brown or purple brown when mature, surface distinctly reticulate when dry, nerves pale and distinct, margins smooth; beak 0.5-0.7 mm long, pale, margin entire, crura 0.2-0.3 mm long; stipe 0.3-0.4 mm long. Stigmas 3. Nut 2.4-2.5 x 1.1-1.3 mm, dark brown to grey-brown, trigonous, ovoid, crowned with persistent style base.

Similar Taxa

Most closely allied to Carex spinirostris Colenso from which it differs by its restriction to ultramafic substrates in exposed situations or under low scrub, small weakly caespitose to caespitose growth habit, basal sheaths pale brown to straw-coloured, erect culms with a bulbous base, erect spikes borne on short peduncles (2-5 mm – up to 25 mm in shade specimens), bright green leaves which are 1.8-3.2 mm wide, light green to pale brown glumes, pale brown to purple brown glumes, and an ovoid, trigonous, dark brown to grey brown nut. Carex spinirostris is a species of high fertility shaded sites usually in coastal or lowland forest, and well forested offshore islands. It is a densely caespitose (tussock-like) sedge with dark red-brown to purple basal sheaths. The culm bases are not bulbous and are loosely covered in sheaths, while the culms are distinctly drooping. The spikes of C. spinirostris are pendulous, and borne on long peduncles (20-85-100 mm). In this species the leaves are dark green and 2.5-8 mm wide. The glumes are bright red-purple, the mature utricles are red or red-brown and the nut is oblong, triquetrous, yellow, yellow-brown or rarely light brown. Both species have distinctly different chromosome numbers.

Flowering

July - June

Fruiting

July - June

Propagation Technique

Fickle. Best grown in a pot. Seed germinates readily and plants can be grown by division of whole plants. However, in cultivation results are variable and mostly plants die within a few years. Seems to respond well to regular dustings with a magnesium rich fertiliser.

Threats

Not threatened - a naturally uncommon, range restricted species, abundant within its sole known habitat at North Cape.

Chromosome No.

2n = c.63

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

Life Cycle and Dispersal

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

This page last updated on 30 May 2014