The New Zealand Plant Conservation Network

Species

Carex impexa

Etymology

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

Current Conservation Status

2012 - At Risk - Naturally Uncommon

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 - At Risk - Naturally Uncommon
2004 - Range Restricted

Qualifiers

2012 - RR

Authority

Carex impexa K.A.Ford

Family

Cyperaceae

Flora Category

Vascular - Native

NVS Species Code

CAREMP

Structural Class

Sedges

Synonyms

None

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.

Features

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 x 1-1.6 mm diameter, ascending to spreading. Leaf sheaths loose, dull brown, shredding with age. Leaves 45-260 x 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. 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 x 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.

Flowering

November

Fruiting

January - March

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.

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.

Chromosome No.

2n = 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 31 Oct 2014