The Vegetation of the Chatham Islands: General. ‚ 255 
Juncus polyanthemos; where the water is shallow near margin of the Green 
Lake there is a belt of 7ypAa. 
4. Forest. 
Virtually the whole of Sunday Island is forest-clad, — a distinct expression 
of climate. The forest may be divided into the two classes, wei? an : 
Wet forest is composed of a mixture of trees none of which is dominant. 
The principal trees are: — Ascarina lanceolata, Melicytus ramiflorus, Notho- 
panax arboreum, Rapanea kermadecensis and Coprosma acutifolia. Metrosi- 
deros villosa, of huge dimensions, occurs in places. Frequently one species or 
another makes a pure stand. Rhopalostylis Cheesemanii and Cyathea kermade- 
censis are generally extremely plentiful. The abundance of epiphytic ferns 
is a striking feature. 
Dry forest is characterised by the dominance of Metrosideros villosa. 
The average height is some 20 m; there are 3 tiers of vegetation. 
combinations form the lowermost tier in different localities, e. g.: — Polystichum 
aristatum ı—2 m high may make an impenetrable mass, or Nephrolepis cor- 
difolia occupy wide areas, its matted roots spreading over the ground or fallen 
logs or climbing the tree-fern trunks, or again the underground be merely a 
dense mass of the stems of Macropiper. The second tier may consist of 
small trees, the palm and tree-ferns, the first-named being especially — Meli- 
cope ternata, Boehmeria dealbata, Coriaria ruscifolia, Corynocarpus laevigata, 
Melicytus ramiflorus, Rapanea kermadecensis, Myoporum laetum and Coprosma 
acutifolia. In places the palm forms pure stands (see Plate LV, Fig. 84). The 
third tier consists of the Metrosideros together with LEN and Myoporum 
which almost equal it in stature. The forest-roof is fairly dense 
