The New Zealand Plant Conservation Network

Species

Carex decurtata

Etymology

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

Common Name(s)

Sedge

Current Conservation Status

2012 - Data Deficient

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 - Sp

Authority

Carex decurtata Cheeseman

Family

Cyperaceae

Flora Category

Vascular - Native

NVS Species Code

CARDEC

Structural Class

Sedges

Synonyms

Carex cryptocarpa Cheeseman

Distribution

Endemic. South Island from Canterbury to Otago, mainly known from the Mackenzie Basin (particularly from Lakes Tekapo, Pukaki and nearby tarns).

Habitat

A plant of lake, tarn margins and river sides, preferring open stony ground or situations with little surrounding vegetation. Tolerant of long period sof water immersion.

Features

Densely tufted bright green, bronze green to yellow-green, diminutive sedge of river terraces, lake and wetland margins. Culms 20-70 mm long, enclosed by light to dark brown leaf-sheaths almost to their apex. Leaves much longer than culms, 30-90 x 0.5-1 mm, almost flat bright green, bronze green to yellow-green, concavo-convex, almost flat, linear, rather rigid and coriaceous, margins scabrid, gradually tapering to a subacute apex, incurved when dry; sheaths twice as broad as lamina, pale brown with chartaceous to membranous margins. Inflorescence a crowded head of 3-5 spikes. Terminal spike male; lower spikes female, 4-8 mm long, ovoid or oblong-ovoid, greenish-brown, sessile or the lowermost rather shortly pedunculate; spikes subtended by leaf-like bracts which are longer than the inflorescence. Glumes less than or of equal length to the utricles, ovate to orbicular, acute or with the midrib extended into a long scabrid awn, nerved, membranous, red-brown with a pale centre and margin, or pale straw-coloured. Utricles 2.5-3 x 1.5 mm, plano-convex to subtrigonous, broadly ovoid, light brown, turgid at the back, faintly nerved, spreading, margins thickened and serrated toward apex, beak 0.5 mm long, scabrid, crura acutely cleft, scabrid; stipe absent although utricle narrows towards base (a pseudostipe). Stigmas 3. Nut 2 mm long, grey-brown, trigonous.

Similar Taxa

Close to C. hectorii Petrie from which it differs by the light brown rather than dark brown utricles, densely tufted rather than spreading shortly rhizomatous habit, and bright green, bronze green to yellow-green, rather than blue-green to red-green leaves.

Flowering

October - January

Fruiting

October - July

Propagation Technique

Easily grown by division of whole plants and fresh seed. Somewhat fickle in dry or humid climates and does best in a small pot.

Threats

A naturally uncommon species largely confined to the intermontane basins of Canterbury and Otago. In some palces it is now at risk from canalisation, dairy farming (irrigation mainly) and the resultant influx of weed species. Its conservation status may require reassessment.

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 29 May 2014