T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Cyperus ustulatus (Giant umbrella sedge) Native

Kingdom:   Plantae
(unranked):        Angiosperms
(unranked):        Monocots
(unranked):        Commelinids
Order:       Poales
Family:      Cyperaceae
Genus:      Cyperus
Species:     C. ustulatus
Binomial name: Cyperus ustulatus
Basionym name: Ustilago gardneri
Synonyms: Mariscus ustulatus
Common names: Giant umbrella sedge, Coastal cutty grass, Cyperus, Upokotangata, Toetoe, Toetoe upokotangata, etoe whatu-manu; Toetoe whatu-pākau.

Cyperus ustulatus is a vigorous native sharp-edged swamp grass (sedge) forming large clumps up to 2 m tall. It is found growing in damp open areas in coastal and lowland habitats, such seepages, stream sides, lagoon, and wetland and estuary margins.
It is common on the North Island, the north of the South Island, the South Islands West Coast and on the Kermadec islands. It is not common on the east coast of the South Island. It is rare on the Chatham Islands.
The tough, light green leaves are up to 1.2 m long and are 8-15 mm wide. The leaf, keel and stem margins have minute sharp teeth that can cause very deep cuts.
The stems sharply 3-angled.
Flowering occurs between July – December. The inflorescences are held by a cluster of leaves at the top of the plant. 
A lot of Inflorescences of Cyperus ustulatus can be infected with Bauerago gardneri. This causes abortion of fruits and etiolated glumes in host plant (this produces the plant known as Cyperus ustulatus f. grandispiculosus - which is really a smut induced state of Cyperus ustulatus (Info from Nature Watch).
Long, dark brown seed heads develop July to April.
Cyperus ustulatus is used for wetland revegetation and environmental plantings but it is generally considered too vigorous for most garden situations.

History of use.
Colenso 1869 reported that the Maoris stripped off outside edges of the leaves and use them for mats, baskets and for kite making.  An upoko-tangata kite was featured on a set of matariki (Maori New Year) stamps issued by New Zealand Post in 2010. http://www.nzhistory.net.nz/media/interactive/matariki-stamps-2010
They also use the leaves as an outer thatch on their whares (dwellings).
Medically the pith was boiled with water, strained and used in the North Auckland districts for kidney trouble (Adams 1945).

Cyperus ustulatus growing in a roadside ditch. The weed Cyperus eragrostis the Umbrella Sedge (light green) is growing in the front.

Cyperus ustulatus growing on side of a drain.

The inflorescences.


The heavily keeled leaves

Thanks to Wikipedia for text and information: