Carex ternaria
Common names
southern cutty grass, rautahi
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Sedges
Detailed description
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 × 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.
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.
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2022-2023 using the New Zealand Threat Classification System (NZTCS) – more information about this can be found on the NZTCS website. This report includes replaces all previous NZTCS lists for vascular plants. Previous assessments can be found here.
Please note, threat classifications are often suggested by authors when publications fall between NZTCS assessment periods – these interim threat classification statuses has not been assessed by the NZTCS panel.
- Conservation status of vascular plants in Aotearoa New Zealand, 2023. 2024. Peter J. de Lange, Jane Gosden, Shannel P. Courtney, Alexander J. Fergus, John W. Barkla, Sarah M. Beadel, Paul D. Champion, Rowan Hindmarsh-Walls, Troy Makan and Pascale Michel Department of Conservation. Source: NZTCS and licensed by DOC for reuse under the Creative Commons Attribution 4.0 International licence.
2023 | At Risk – Declining | Qualifiers: DPR, DPS, DPT, RR
Detailed taxonomy
Family
Cyperaceae
Synonyms
Carex martinii Petrie
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
October–December
Fruiting
December–July
Life cycle and dispersal
Nuts surrounded by inflated utricles are dispersed by granivory and wind (Thorsen et al., 2009).
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.
Wetland plant indicator status rating
Information derived from the revised national wetland plant list prepared to assist councils in delineating and monitoring wetlands (Clarkson et al., 2021 Manaaki Whenua – Landcare Research Contract Report LC3975 for Hawke’s Bay Regional Council). The national plant list categorises plants by the extent to which they are found in wetlands and not ‘drylands’. The indicator status ratings are OBL (obligate wetland), FACW (facultative wetland), FAC (facultative), FACU (facultative upland), and UPL (obligate upland). If you have suggestions for the Wetland Indicator Status Rating, please contact: [Enable JavaScript to view protected content]
FACW: Facultative Wetland
Usually is a hydrophyte but occasionally found in uplands (non-wetlands).
Other information
Etymology
carex: Latin name for a species of sedge, now applied to the whole group.
NVS 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.
CARTER
Chromosome number
2n = c.66
Previous conservation statuses
2017 | Not Threatened
2012 | Not Threatened
2009 | Not Threatened
2004 | Not Threatened
Referencing and citations
References and further reading
Moore LB, Edgar E. 1970. Flora of New Zealand, Volume II. Indigenous Tracheophyta: Monocotyledones except Gramineae. Government Printer, Wellington, NZ. 354 p.
Thorsen MJ, Dickinson KJM, Seddon PJ. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 11: 285–309.
Attribution
Fact Sheet prepared by P.J. de Lange (10 August 2006). Description adapted from Moore and Edgar (1970)
Some of this factsheet information is derived from Flora of New Zealand Online and is used under a Creative Commons Attribution 3.0 New Zealand licence.
NZPCN Fact Sheet citation
Please cite as: de Lange, P.J. (Year at time of access): Carex ternaria Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/carex-ternaria/ (Date website was queried)