Included here is the Chatham archipelago situated in the South Pacific some 450 miles east of New Zealand. The largest is Chatham Island measuring about 30 miles in length while the next largest, Pitt Island, barely measures 8 miles.

Chathamian Swamp Formations

The curious restiaceous plant Leptocarpus simplex often dominates the swamps, which are largely confined to the central and northern parts of Chatham Island. These are also no doubt the places to find the endemic carices Carex chathamica and C. ventosa (Cyperaceae). In the slightly dryer areas, less likely to be subject to seasonal flooding, Coprosma propinque is usually the main species together with tall grasses such as Arundo conspicua, several Epilobium species and the endemic Astelia chathamica (Asteliaceae).

Chathamian Bog Formations

On some of the marshy land adjacent to lakes can be found the endemic Aciphylla traversii (Apiaceae), but in general the bog formations can be roughly divided into Sphagnum bogs, Lepyrodia-Olearia bogs, Phormium bogs and Dracophyllum bogs. The remaining Sphagnum bogs are considered to be very primitive and thought to have been much more extensive in the past. In the wettest areas the only associated taxa are usually Carex and Isolepis, but in the dryer areas scattered plants of Hierchloe redulens and the endemic Poa chathamica (Poaceae) occur. Hollows between the Sphagnum are the haunt of insectivorous plants such as Drosera binata and Utricularia monanthos and in places the unusual fern Schizaea fistulosa can be found. The Lepyrodia-Olearia formation seems to be the natural succession from Sphagnum bog as the ground becomes dryer. The two main species are Lepyrodia traversii and the endemic Olearia semidentata (Asteraceae). The former species was also thought to be endemic but has since been found in New Zealand. Other associated plants include Gleichenia circinata and the endemic Gentiana chathamica (Gentianaceae). In areas too dry for Olearia semidentata, its close relative the endemic Olearia chathamica (Asteraceae) may become the main species. This species can form dense thickets devoid of other plants, but where it is less dense species such as Lomaria procera and Pteris esculenta grow in the undergrowth. The remaining Phormium bogs are mainly confined to the banks of the tableland streams. The dominant Phormium tenax is often associated with species such as Cotula asiatica and Juncus planifolius. The Dracophyllum formation is transitional vegetation between bog and forest. It is characterised by the endemic Dracophyllum paludosa (Epacridaceae), but small trees of the related endemic Dracophyllum arboreum may also be present. The endemic Olearia semidentata (Asteraceae) may also be well represented and in places becomes the dominant species. The ground flora includes species such as Pratia arenaria and the endemic Poa chathamica (Poaceae).


Cockayne, L. 1958. The Vegetation of New Zealand. H. R. Engelmann (J. Cramer).

Cockayne, L. 1902. A short account of the plant-covering of Chatham Island. Transactions of the New Zealand Institute, 34: 243-325.

Molloy, L. 1994. Wild New Zealand. The MIT Press, Cambridge, Massachusetts.

Northcroft, E. F. 1975. Adventive flora of the Chatham Islands. New Zealand Journal of Botany, 13: 123-129.