Species

Carex geminata

Etymology

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

Common Name(s)

Cutty grass, Rautahi

Current Conservation Status

2012 - Not Threatened

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 - Not Threatened
2004 - Not Threatened

Authority

Carex geminata Schkuhr

Family

Cyperaceae

Flora Category

Vascular - Native

NVS Species Code

CARGEM

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

Synonyms

Carex ternaria var. gracilis Cheeseman, C. confusa Hamlin.

Distribution

Endemic. Found throughout the North, South and Stewart Islands.

Habitat

Coastal to lower montane in freshwater wetlands, along river and stream banks, lake margins, and in damp seepages, pond margins and clearings within forest. Preferring fertile to mid-fertile wetlands.

Features

Rhizomatous, robust bright-green to yellow-green sedge, 0.5-1.2 m tall. Culms 1-5-3.5(-5) mm diam., triangular in cross-section, very sharply scabrid. Basal sheaths dull grey-brown or purple-brown. Leaves numerous, > culms (2-)5-9(-11), wide, double-folded, margins very scabrid. Spikes (10-)15-24, yellow-green, grass-green, or dark-green mottled red or purple, all pedunculate, pendulous, rather narrow, often twisted and "worm-like". Glumes dark red-purple, (excluding awns) more less same length as utricles, narrow-oblong, truncate or emarginate with a hispid awn of variable length. Utricles (2-)2.3-2.9(-3.5) x 1.2-1.7(-2) mm, biconvex, compressed at base, tapering evenly above, green-, red- or yellow-brown, 3-5-nerved, margins glabrous, beak minute or 0.2 mm long.

Similar Taxa

C. geminata has frequently been confused with C. lessoniana Steud. This species often grows in similar habitats, but can be distinguished by the compact inflorescences, with wider, though smaller, usually erect spikelets, and by distinctly beaked utricles. A similar species C. ternaria Boott is occasionally cultivated on the New Zealand mainland, this species is very much larger (up to 3 m tall), dark green sedge with much larger spikes and glumes which are conspicuously awned.

Flowering

(September-) October-November (-December)

Fruiting

October - March

Propagation Technique

Easily grown from fresh seed and by the division of established plants. Although a wetland species C. geminata will grow well in most soils and moisture regimes. Does best in full sun.

Threats

Not Threatened

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).

Where To Buy

Not commonly cultivated, and plants offered by this name by many nurseries are usually other quite unrelated species, including the Northern Hemisphere C. pendula and the New Zealand subantarctic endemic C. ternaria.

Notes on taxonomy

This taxon includes two entities, one probably better regarded as an allied but distinct, possibly unnamed species which differs from true C. geminata by its much broader, often yellow-green leaves, longer narrower spikelets, preference for open sunny sites within coastal and lowland wetlands, and also by distinct differences within the nrDNA ITS sequence region.

Attribution

Fact Sheet prepared by P.J. de Lange (10 August 2006). Description adapted from Moore and Edgar (1970)

References and further reading

Moore, L.B.; Edgar, E. 1970: Flora of New Zealand. Vol. II. Government Printer, Wellington.

Thorsen, M. J.; Dickinson, K. J. M.; Seddon, P. J. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 2009 Vol. 11 No. 4 pp. 285-309

This page last updated on 18 Jun 2015