The New Zealand Plant Conservation Network

Species

Carex ternaria

Etymology

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

Common Name(s)

Southern Cutty Grass, Rautahi

Current Conservation Status

2012 - Not Threatened

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 - Not Threatened
2004 - Not Threatened

Authority

Carex ternaria Boott

Family

Cyperaceae

Flora Category

Vascular - Native

NVS Species Code

CARTER

Structural Class

Sedges

Synonyms

Carex martinii Petrie

Distribution

Endemic. Chatham, Antipodes and Auckland Islands

Habitat

Widespread along stream, lake and pond margins and in seepages, flushes, and around shallow ephemeral pools. Usually in open, well lit situations but also may be fringing streams running through successional forest.

Features

Stoutly rhizomatous, widely creeping, robust sedge forming diffuse dark green to dark glaucous green clumps up to 3 m tall. Plants dying back to rhizomes in cold conditions. Rhizome 5–10 mm diameter, lignaceous, closely covered with red-brown sheaths. Culms 0.3–3.0 m tall, 3–5 mm wide, triquetrous, harshly scabrid; basal sheaths red-brown, margins shredding into fibres with age. Leaves > culms, up to 3.2 m long, 4–17 mm wide, double-folded, margins and keel finely scabrid. Spikes 7–18, in both sexes varying from 10–80 m in length, distant, peduncles usually ± = or > spikes, stout, stiff and erect, or more slender and drooping; upper 2–7 spikes male, c.4–6 mm diameter (excluding very prominent awns); lower spikes female, 5–8 mm. diameter, lowest spikes geminate or ternate. Glumes of male spikes ± truncate to acute, with scabrid awns occasionally up to 10 mm long; glumes of female spikes (excluding awn) ± = utricles, narrow-lanceolate to elliptic-lanceolate, acute, red-brown, membranous, with lighter brown, broad midrib prolonged as a finely scabrid awn up to 6 mm long (awn occasionally very dark red). Utricles c.2.0–3.0 x 1.5–2.0 mm., plano-convex to biconvex, elliptic-obovoid, ± turgid, light yellow-brown, sometimes red-brown towards the base, nerves 5 or more on each face, margins smooth; beak c.0.2–0.4 mm long, often lighter brown, very narrow, orifice glabrous, very slightly bifid; stipe c.0.3 mm long, narrow. Stigmas 2. Nut 1.5–2.0 mm. long, biconvex, obovoid, lustrous, brown.

Similar Taxa

In its natural habitat Carex ternaria cannot be confused with any other carex species because it is allopatric from its closest relatives C. coriacea Hamlin, C. geminata Schkuhr, and C. lessoniana Steud. However, C. ternaria is now occasionally available from plant nurseries and distinction between it and these allied species is not always clear. The most obvious difference is stature as C. ternaria is much taller, regularly attaining heights of over 2 m up to a maximum of 3 m. Like C. coriacea it is deciduous (though only in cold weather), and it differs from all three species by its much larger spikes and conspicuously awned glumes.

Flowering

October - December

Fruiting

December - July

Propagation Technique

Easily grown from fresh seed and by the division of whole plants. Prefers a permanently damp, acidic soil. Plants die back in cold conditions. An attractive sedge for a large garden where it should be planted on the margin of ponds or slow flowing streams.

Threats

Not Threatened

Chromosome No.

2n = c.66

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 18 Jun 2015