Carex impexa
Biostatus
Native – Endemic taxon
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: DPS, DPT, RR
Category
Vascular
Structural class
Sedges
Detailed description
Tufted, stiffly spreading; shortly rhizomatous, bronze-green, green, brown-green, red-green to red sedge of calcareous substrates. Rhizomes up to 35 mm; 1–1.36 mm diameter, covered by brown striated bracts. Culms 14–900 × 1–1.6 mm diameter, ascending to spreading. Leaf-sheaths loose, dull brown, shredding with age. Leaves 45–260 × 1.5–3.6 mm, equal to or greater than, or less than culms, channelled, stiff, recurved, margins and keel red, thickened, scabrid; apex scabrid, trigonous, acuminate. Inflorescence of 3–5, brown, erect, mostly sessile, congested spikes. Spikes: terminal spike male 7–12 mm long; remaining spikes female, 6–10 mm long. Glumes 1.8–2.4 mm, < utricles, brown, ovate-rotund, concavo-convex, subcoriaceous, 3-veined, green maturing brown; margins membranous, mostly entire, becoming lacerate with age, awned or not. Stamens 3. Utricles 2–2.7 × 1–1.4 mm, subtrigonous, broad-elliptic to obovate, brown to dark-brown, smooth, beakless or with short beak, if beaked, then orifice shallowly bifid or entire, crura short. margins below beak sometimes scabrid. Stigmas 3. Nut brown, trigonous.
Similar taxa
Allied to Carex dallii Kirk and C. dissita Sol. ex Boott. It differs from C. dallii and C. dissita in having a congested inflorescence. In C. dallii the 3–5 spikes are approximate with typically the lower one distant, while those of C. dissita are spaced at increasingly longer intervals down the inflorescence. Specifically from C. dallii, C. impexa differs by its broad (1.5–3.6 cf 1–1.6 mm) leaves which are stiff, recurved, green to red-brown, bronze-green (or rarely red) rather than laxly recurved and uniformly red. In C. impexa the basal sheaths are dull brown rather than light brown to reddish. The utricles of C. dallii are narrow-ovoid to almost oblong, dark red-brown and shortly beaked, while in C. impexa they are broad-elliptic to obovate, brown to dark brown, beakless to scarcely beaked. In C. impexa the female glumes are ovate to rotund, brown, while C. dallii glumes are ovate, and red-brown coloured.
Distribution
Endemic. South Island, North West Nelson, Kahurangi National Park from the Gouland Downs and Pikikiruna Range south to the Matiri Range.
Habitat
A species of forested or tussock-grassland, rupestral communities overlying weakly weathered limestone, marble and calcareous mudstone/siltstone. In these sites Carex impexa is found beneath cliffs, on ledges, debris slopes, boulder field and around sinkholes in sites from 630–1400 m.a.s.l.
Threats
A sparsely distributed, naturally uncommon species of calcareous substrates which does not appear to be under any obvious threats. Carex impexa is uncommon but still present on the Canaan Downs and Takaka Hill portion of the Pikikiruna Range but it is there where it does seem to have declined. Elsewhere it seems secure for the time being.
Detailed taxonomy
Genus
Family
Synonyms
None
Endemic taxon
Yes
Endemic genus
No
Endemic family
No
Ecology
Flowering
November
Fruiting
January–March
Life cycle and dispersal
Nuts surrounded by inflated utricles are dispersed by granivory and wind (Thorsen et al., 2009).
Propagation technique
Does best in full sun, in a pot, in free draining soil enriched with lime. It does not like humid climates. Tends to be rather short-lived, and needs frequent repotting to maintain.
Other information
Etymology
carex: Latin name for a species of sedge, now applied to the whole group.
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.
CAREMP
Chromosome number
2n = 66
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: RR
2012 | At Risk – Naturally Uncommon | Qualifiers: RR
2009 | At Risk – Naturally Uncommon
2004 | Range Restricted
Regional conservation statuses
Referencing and citations
References and further reading
Ford KA. 1998. Carex impexa (Cyperaceae), a newly described sedge from New Zealand. New Zealand Journal of Botany 36(4): 587–592. https://doi.org/10.1080/0028825X.1998.9512596.
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 (31 May 2005). Description based on Ford (1998)