144 Transactions. 



sideros among wliich they grow. The principal plants of this tier are Meli- 

 cytus ramiflorus, Rapanea kermadecensis, Coprosma acutifolia, Melicope 

 ternata, Corynocarpus Icevigata, Myoporum Iretum, Coriaria sarmentosa, 

 Boehmeria dealbata, Rhopalostylis Baueri, and Cyathea Milnei. 



Near the coast, on Low Flat and other places, Pittosporum crassifoliuni 

 occurs, while in Coral Bay and elsewhere are clumps of Pisonia Brunoniana, 

 each tree stripped of its bark as far as goats can reach. 



In the more sheltered places Rhopalostylis Baueri forms picturesque 

 groves. There is seldom much undergrowth where these palms are plentiful. 



The third tier of vegetation in the dry forest is composed almost ex- 

 clusively of Metrosideros villosa 20 m. tall. Two other trees, Corynocarpus 

 IcBvigata and Myoporum Icetum, occasionally equal the Metrosideros in height ; 

 while one, Melicytus ramiflorus, although not more than 15 m. tall, some- 

 times claims a share in the upper tier of foUage. There are large Coryno- 

 carpus trees in several places, but the giant Myopora were only seen in the 

 crater and on the Terraces. A large Melicytus on the Terraces measured 

 15 m. in height, and had four principal stems, 80 cm,, 110 cm., 110 cm., and 

 125 cm, in circumference respectively. 



The forest-roof is usually fairly dense, and this factor determines the 

 slender habit of the trees forming the second tier and regulates the dis- 

 tribution of the undergrowth. 



Epiphytes are not a conspicuous feature in dry forest. The trmiks of 

 GyathecB occasionally support Tmesipteris tennensis, Asplenium caudatum, 

 and Nephrolepis cordifolia. Branches of trees, especially the larger hori- 

 zontal ones, and leaning stems, too, afiord situations for a little moss, Cyclo- 

 phorus serpens, Poly podium diver si folium, and Asplenium fiaccidum (small 

 erect form). 



(2.) Wet forest : Unlike the dry forest, the wet forest is composed of 

 a mixture of trees no one of which is predominant. Its appearance from 

 above is varied by its different shades of green, while the graceful heads of 

 palms and tree-ferns are thickly scattered about among the foliage. The 

 average height on the summits of the hills is about 10 m., but in valleys 

 and on sheltered slopes the tree-ferns {Cyathea kermadecensis) are 15-20 m, 

 tall, and the forest-trees rather less. 



On Moumoukai, the highest and wettest portion of the island, the forest- 

 floor is everywhere covered with (1) mosses ; (2) low ferns — Dryopteris 

 glabella, Blechnum norfolkianum, Polypodium diversifolium, Hymenophyllum 

 demissum ; (3) dead leaves— notably Cyathea fronds and palm-leaves — and 

 sticks ; (4) roots of trees, fallen tree-fern stems, logs, &c., covered with 

 mosses and the above four ferns. 



Fallen trunks of tree-ferns are plentiful on the floor of the wet forest. 

 These are invariably covered with mosses, Hymenophyllum demissum, Poly- 

 podium diversifolium, and on the under-side Trichomanes venosum, or perhaps 

 T. humile. 



On Big Hill the undergrowth is most dense, and there is a smell of rotting 

 vegetation. Pteris comans is the principal plant, and its general height 

 is 2 m. Under the Pteris grow Dryopteris glabella and Blechnum norfolki- 

 anum. 



The trees of the upper forest grow close together, average 10 m. or more 

 in height, and have much-branched heads of dense foliage. 



Metrosideros villosa is here not the dominant tree, but is usually of la^-ge 

 proportions, with immense prostrate trunks supported by numerous root 

 props. The direction in which the trunk is lying is almost invariably north 



