None - this species is a recently recognised segregate of the New Zealand endemic C. ustulatus A.Rich
Vascular – Native
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.
2n = 112-114
Current conservation status
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2017 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2012 and replaces all previous NZTCS lists for vascular plants. Authors: By Peter J. de Lange, Jeremy R. Rolfe, John W. Barkla, Shannel P. Courtney, Paul D. Champion, Leon R. Perrie, Sarah M. Beadel, Kerry A. Ford, Ilse Breitwieser, Ines Schönberger, Rowan Hindmarsh-Walls, Peter B. Heenan and Kate Ladley.
2012 | At Risk – Declining | Qualifiers: RR
Previous conservation statuses
2009 | At Risk – Declining
2004 | Not Threatened
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)
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.
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.
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).
July - December
July - April
Nuts are dispersed by water, granivory and attachment (Thorsen et al., 2009).
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
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.
cyperus: From the ancient Greek name for sedge, kypeiros
insularis: From the Latin insula ‘island, pertaining to or growing on islands
Fact Sheet prepared for NZPCN by P.J. de Lange (31 July 2004). Description adapted from Heenan & de Lange (2005).
References and further reading
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.
Please cite as: de Lange, P.J. (Year at time of access): Cyperus insularis Fact Sheet (content continuously updated). New Zealand Plant Conservation Network. https://www.nzpcn.org.nz/flora/species/cyperus-insularis/ (Date website was queried)