Kermedecian Maritime Vegetation
On the rocky cliffs, tussocks of Poa polyphylla together with Apium prostrata, Asplenium obtusatum, Lobelia anceps, Mariscus ustulatus, Mesembryanthemum australis, Parietaria debilis, Samolus repens stricta, Scirpus nodosa, Tetragonia expanse and the endemic Coprosma petiolata (Rubiaceae) are the principal plants. The endemic shrub Coprosma petiolata usually occurs in a stunted or prostrate form closely hugging the cliffs. Other endemic species include Scaevola gracilis (Goodeniaceae), which can occasionally be found growing with Coprosma petiolata. In some of the crevices where deeper soils occur, stunted trees of Metrosideros villosa cling to the cliffs, while at the foot of sea cliffs, tussocks of Mariscus ustulatus may be present together with species such as Pteris comans and Hypolepis tenuifolia. Further seaward, just above high water the mangrove shrub Myoporum laetum becomes the dominant species. This zone may also include trees such as the endemic Rapanea kermadecensis (family?) and the fantastically branched Pisonia brunoniana. Proper sand dunes and gravel flats only occur on Sunday Island and in both cases Ipomoea pes caprae is one of the more important species. On the sand dunes, the dune grass Eleusine indica can be found growing amongst the Ipomoea together with Apium prostratum, Imperata cheesemani and Scirpus nodosa. Other species found on the gravel flats include Ageratum conyzpoides, Deyeuxia forsteri and the endemic Scaevola gracilisI (Goodeniaceae).
Kermedecian Inland Cliff and Rock Formations
This habitat provides refuge for several species that are being suppressed in the forests by introduced goats including the endemic Erechtites kermadecensis (Asteraceae) and the ancient Psilotum triquetrum. On Macauley Island the rock ravines provide habitat for the endemic Boehmeria dealbata (Urticaceae).
Kermedecian Inland Forest formations
These forests can be divided in to two types, broadly classified as wet hill forest (above an altitude of about 200 m) and dry lowland forest. Amongst the dominant trees of the lowland forest are the endemic Coprosia acutifolia (Rubiaceae), Homolanthus polyandrous (Euphorbiaceae), Metrosideros kermadecensis (Myrtaceae), Rapanea kermadecensis (family?) and the endemic tree fern Cyathea milnei (Cyatheaceae). Several of these are adapted to seasonal dryness - Homolanthus polyandrus is semi-deciduous, while others such as Rapanea kermadecensis are able to roll their leaves. Although less conspicuous than in the wet forests, the epiphytes may include Asplenium caudatum and Nephrolepis cordifolia, while the forest floor tends to be dominated by tree seedlings with species such as Corynocarpus laevigata and Rapanea kermadecensis often forming dense patches. In the wet forest the endemic trees include Ascarina lanceolata (Chloranthaceae), Neopanax kermadecense (Araliaceae) and the palm Rhopalostylis cheesemanii (Arecaceae), together with endemic tree fern Cyathea kermadecensis (Cyatheaceae). Other less common trees include the endemic Boehmeria dealbata (Urticaceae). Amongst the luxuriant cover of epiphytes is the ancient psilopsid Tmesipteris tannensis, ferns such as Asplenium flaccidum, Hymenophyllum demissum, Cyclophorus serpens, clubmosses such as Lycopodium billardieii and flowering plants such as Peperomia endlicheri. The forest floor is also richly covered in lower plants with many mosses and ferns such as Blechnum norfolkianum and Drypteris glabella.
Further information required.
References
Balgooy, Van. M. M. J. 1960. Preliminary plant geographical analysis of the Pacific. Blumea, 10: 385-430.
Balgooy, Van. M. M. J. 1969. A study of the diversity of island floras. Blumea, 17: 139-178.
Molloy, L. 1994. Wild New Zealand. The MIT Press, Cambridge, Massachusetts.
Mueller-Dombois, D. & Fosberg, F. R. 1998. Vegetation of the Tropical Pacific Islands. Springer.
Oliver, R. B. 1910. The vegetation of the Kermadec Islands. Transactions and Proceedings of the New Zealand Institute, 42: 118-175.
Sykes, W. R. & West, C. J. 1996. New records and other information on the vascular flora of the Kermadec Islands. New Zealand Journal of Botany, 34: 447-462.
Wace, N. M. 1960. The botany of southern oceanic islands. The Royal Society Expedition to Southern Chile. Proceedings of the Royal Society, 152: 475-490.