Species

Cyperus insularis

Etymology

Cyperus: From the ancient Greek name for sedge, kypeiros
insularis: From the Latin insula 'island, pertaining to or growing on islands

Current Conservation Status

2012 - At Risk - Declining

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 - Declining
2004 - Not Threatened

Qualifiers

2012 - RR

Authority

Cyperus insularis Heenan et de Lange

Family

Cyperaceae

Flora Category

Vascular - Native

NVS Species Code

CYPINS

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

None - this species is a recently recognised segregate of the New Zealand endemic C. ustulatus A.Rich

Distribution

Endemic. Known only from the Kermadec, Three Kings Islands, and northern North Island and associated offshore islands south to Port Waikato and Moutohoura (Whale) Island (Bay of Plenty)

Habitat

Northern offshore islands, and rocky headlands, usually in association with sea bird nesting grounds, though on the Kermadec Islands, where it is the only species present it is also present along sandy beaches and in swamps.

Features

Robust sedge up to 2 m tall with leaves crowded at base of culms. Culms stout, triquetrous, glabrous, striated, green, rarely brown in distal part, at base, upright at flowering, collapsing at seed fall. Leaves 1.4 -3.2 mm x 1-2 m, grey green, strongly keeled, leaf margin and keel sharply scabrid, sheath light pink to light purple-pink. Inflorescence a terminal umbel of 6-12 unequal rays, each subtended by a leaf-like involucral bract, these 0.3-3.2 mm x 0.1-1.15 m, grey-green, base green, often flushed light pink to purple-pink, or rarely pale brown. Spikelets 9-12 mm long, glumes 3-5.8 x 2-2.8 mm, ovate-oblong or ovate, green some times pale green or translucent, distal end and margin red-brown, drying yellow-brown to light brown, keeled, mcuronate or obtuse, crowded into a dense spike 40-60 mm long. Stamens with persistent filaments. Nut 1.6-1.7 mm, red-brown to orange-brown, oblong to broadly oblong.

Similar Taxa

Distinguished from C. ustulatus A.Rich. by the grey-green leaves and involucral bracts, leaf sheaths light pink to purple-pink the culm/involucral bract junction green, pink or rarely pale brown, by the stout, usually branched rays, and by the culms which collapse after flowering. There are other floral characters which also distinguish these species, for these and other details see Heenan & de Lange (N.Z.J.Bot. 43: 351-359 (2005) - see link below).

Flowering

July - December

Fruiting

July - April

Propagation Technique

Easily grown from fresh seed, and often self sows in gardens. A quite attractive plant which may in time prove popular in cultivation. However it should be planted with caution, the leaf, keel and culm margins are very sharp and can cause very deep cuts

Threats

Declines are happening on Raoul and Macauley Islands, and there is some evidence of this also in the North Island part of its range. The nature of the decline is not clear, though in some places, such as Macauley Island it appears to be part of natural succession while on Raoul the decline at Denham Bay may be due to the spread of buffalo grass (Stenotaphrum secundatum). Within the mainland portion of its North Island range, the species appears restricted to sites frequented by sea birds, especially their nesting grounds, and it seems that as these habitats have been lost, so too has the Cyperus.

Chromosome No.

2n = 112-114

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

Life Cycle and Dispersal

Nuts are dispersed by water, granivory and attachment (Thorsen et al., 2009).

Attribution

Fact Sheet prepared for NZPCN by P.J. de Lange (31 July 2004). Description adapted from Heenan & de Lange (2005).

References and further reading

Heenan, P.B.; de Lange, P.J. 2005: Cyperus insularis (Cyperaceae), a new species of sedge from northern New Zealand. New Zealand Journal of Botany 43: 351-359.

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 11: 285-309.

This page last updated on 31 Oct 2014