Carex ventosa
Common names
Chatham Islands forest sedge
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Sedges
Detailed description
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 × 1–2.5–4 mm, trigonous, mostly smooth though scabrid below inflorescence. Basal sheaths brown. Leaves ≥ 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 × 6–8–10 mm. Glumes (excluding awn) ≤ 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 × 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 haulouts and seabird 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 × 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.
Distribution
Endemic, Chatham Islands where it is known from Chatham (Rekohu), Pitt, Mangere, Little Mangere, South East, Star Keys and Rabbit Islands.
Habitat
A widespread sedge of Chatham Island lowland forest. Not found in deep peat and mainly associated with dune forests, coastal forests and tall scrub.
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.
- 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 – Naturally Uncommon | Qualifiers: DPR, DPS, DPT, IE, RR
Threats
A common, widespread island endemic. It is not threatened on the Chatham Islands.
Detailed taxonomy
Family
Synonyms
Carex mcclurgii Petrie
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
September–January
Fruiting
October–May
Life cycle and dispersal
Nuts surrounded by inflated utricles are dispersed by granivory and wind (Thorsen et al., 2009).
Propagation technique
Easily grown by division 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.
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]
FACU: Facultative Upland
Occasionally is a hydrophyte but usually occurs 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.
CARVEN
Chromosome number
2n = c.62-64
Previous conservation statuses
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.
- 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.
2017 | At Risk – Naturally Uncommon | Qualifiers: IE, RR
2012 | At Risk – Naturally Uncommon | Qualifiers: IE, RR
2009 | At Risk – Naturally Uncommon | Qualifiers: IE
2004 | Range Restricted
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 for NZPCN 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 ventosa Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/carex-ventosa/ (Date website was queried)