Carex obtusifolia
Common names
fine-leaved bastard grass
Biostatus
Native – Endemic taxon
Category
Vascular
Structural class
Sedges
Detailed description
Small tufts to small tussocks, laxly to densely caespitose, sometimes with fine creeping rhizomes. Culms glabrous, trigonous, at flowering similar in length to leaves, at maturity much longer than leaves, 50–400 × 0.3–0.6 mm; basal bracts light brown to yellow-brown, dull, 2–7 mm long. Leaves plano-convex or concavo-convex, rigid, linear, strongly nerved on abaxial surface, erect or ascending, 45–300 × 0.4–0.5 mm; apex obtuse and nerves weak or absent; margins scabrous when young, often becoming glabrous when mature. Spikes oblong, 15–20 mm long; female flowers proximal, 3–7, internodes 1.5–3.0 mm long; male flowers distal, 3–5. Glumes < utricle, deciduous, elliptic-lanceolate to lanceolate, 3.5–5.0 × 1.5–2.0 mm; midrib green; apex subacute to obtuse; margins membranous. Utricles trigonous, elliptic to lanceolate, yellow-green, yellow-brown, or light brown, lateral nerves present but not conspicuous, 5.0–6.2 × 0.9–1.1 mm; stipe and beak both narrow, each c. 1.5 mm long; rachilla exserted beyond utricle, 5.3–6.5 mm long. Nut trigonous, narrow-elliptic to linear, pale brown, dull, 3.0-3.9 × 0.8-1.1 mm
Similar taxa
Previously included within the allied Carex cheesemanniana (Boeckeler) K.A.Ford from which it differs by its much finer (almost capillary) narrower leaves, culms, spikes, and utricles. The utricles are yellow-brown rather than dark brown; and unlike Carex cheesemanniana the glumes are smaller and shorter than the utricle, further the floret internodes are longer than in C. cheesemanniana. The nuts of Carex obtusifolia are narrower and longer than those of C. cheesemanniana. It could also be confused with the forest dwelling Carex lectissima K.A.Ford. That species is distinguished from all other New Zealand Uncinia by the light-coloured striations on the red-brown basal sheaths, and from Carex obtusifolia by the trigonous upper part of the leaf and by the acute rather than obtuse leaf apex.
Distribution
Endemic. New Zealand: North, South and Stewart Islands. In the North Island found only in the mountainous regions of the southern half; in the South Island present mainly west of the main divide (rarely in the east). Found throughout Stewart Island.
Habitat
Wet ground in bogs, damp flushes, hollows, and seepages in tussock grassland, around the margins of clearings, among open scrub, and in open pasture in lowland and low-alpine areas.
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: Sp, DPS, DPT
Detailed taxonomy
Genus
Family
Synonyms
Uncinia obtusifolia Heenan
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
November–December
Fruiting
December–May
Propagation technique
Unknown. However like Carex debilior (F.Muell.) K.L.Wilson it is probably easily grown from fresh seed and by the division of established plants. It probably requires a permanently damp, peaty soil and semi-shaded conditions.
Other information
Etymology
carex: Latin name for a species of sedge, now applied to the whole group.
obtusifolia: With a blunt leaf
Manaaki Whenua Online Interactive Key
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.
CAROBT
Chromosome number
2n = 88
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: Sp
2012 | At Risk – Naturally Uncommon | Qualifiers: Sp
2009 | Not Threatened
2004 | Not Threatened
Regional conservation statuses
Otago: 2024 | Regionally Data Deficient
The regional threat classification system leverages off the national assessments in the NZTCS, providing information relevant for the regional context. Otago conservation status information is sourced from the “Regional conservation status of indigenous vascular plants in Otago” Jarvie S et al. (2024) report.
Referencing and citations
References and further reading
Heenan PB. 1995. Uncinia obtusifolia. (Cyperaceae), a new species of hooked sedge in New Zealand. New Zealand Journal of. Botany 34(1): 11–15. https://doi.org/10.1080/0028825X.1996.10412687.
Attribution
Description and details from Heenan (1995). Fact sheet prepared by Peter J. de Lange 17 August 2006.