Species

Carex demissa

Etymology

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

Common Name(s)

yellow sedge

Authority

Carex demissa Hornem.

Family

Cyperaceae

Brief Description

Grass-like yellowish-green sward-forming plant, with small prickly catkins (spikes) produced along the stems in spring.

Flora Category

Vascular - Exotic

NVS Species Code

CARDEM

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.

Structural Class

Sedges

Distribution

Scattered throughout, common in high rainfall areas such as Westland and Southland.

Habitat

Water body margins, swamps, damp waste places and low-lying areas.

Features

Tufts ± dense. Stems variable, to 30 cm long and much > leaves, but often < leaves, erect or ± flaccid, smooth, subterete. Leaves 1.5-3 mm wide, channelled, dull yellow-green; ligule notched; sheaths almost white, becoming grey. Inflorescence of one terminal pedunculate male spike and 1-4 ± sessile, erect female spikes usually approximate at top of stem but often with a single female spike towards base of stem; subtending bracts > inflorescence, flaccid. Male spike to 2 cm × 2 mm; glumes light brown, ± 4 mm long, obtuse, light brown. Female spikes ± 1 cm × 5 mm; glumes < utricles, ovate, subacute, membranous, brown-tinged. Utricles ± 3 × 1 mm, glabrous, faintly nerved, inflated, yellow-green, obovoid, abruptly narrowed to a bifid beak to 1 mm long. Stigmas 3. Nut obovoid, trigonous.

Similar Taxa

Superficially similar to many Carex species with distinct male and female spikes. Perhaps closest to the related native C. flaviformis, distinguished by the female spike crowded beneath the male spike, not distant as with C. demissa).

Flowering

Spring

Flower Colours

Green

Fruiting

Summer

Year Naturalised

1907

Origin

Europe, eastern Canada

Reason for Introduction

Unknown, seed or soil contaminant.

Control Techniques

Not controlled in New Zealand.

Life Cycle and Dispersal

Seed dispersed by contaminated machinery or waterfowl.

Attribution

Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA). Features description from Healy and Edgar (1980).

References and further reading

Champion et al (2012). Freshwater Pests of New Zealand.  NIWA publication. http://www.niwa.co.nz/freshwater-and-estuaries/management-tools/identification-guides-and-fact-sheets/freshwater-pest-species

Johnson PN, Brooke PA (1989).  Wetland plants in New Zealand.   DSIR Field Guide, DSIR Publishing, Wellington. 319pp.

This page last updated on 21 Aug 2013