Ecological Botany.] SUBANTARCTIC ISLANDS OF NEW ZEALAND. 2l3 



will be a luxuriant growth of Montia fontana and CalUtriche antarctica, forming 

 thick green mats perhaps a square metre in area, together with the long depending 

 shoots of Cotula lanata. 



The vegetation of sheltered drier cliffs may be nearly equally luxuriant, and 

 this depends upon the peat-forming capabilities of the two maritime ferns. On 

 low cliffs just outside the rim of the forest there may be a belt of Stilbocarpa polaris 

 growing intermixed with masses of Asplenium obtusatum, 40 cm. tall, over which, 

 and contrasting with the very dark leaves, may straggle the bluish-green Acaena 

 Sanguisorbae var. antarctica. A second zone will probably be of Poa litorosa, its 

 filiform leaves, a metre or so long, draping the cliff-face, and when massed together 

 looking like a huge beard. 



Where a cliff is more sheltered, Poa foliosa of similar habit is the grass covering. 

 But the most common plants of this formation are Blechnum durum and Asplenium 

 obtusatum, both very dark green in colour, their leaves at times 60 cm. to 80 cm. 

 long, and beneath their massive rhizomes is peat 60 cm. or so in depth (see fig. 9, 

 left-hand top corner). 



Where the adjacent ground is flat, or where a grass meadow comes to the shore, 

 there is generally a belt of Poa foliosa mixed with Carex trifida, and in many places 

 Poa litorosa also. In such places Veronica dliptica, Blechnum durum, Asplenium 

 obtusatum, Acaena Sanguisorbae var. antarctica, Histiopteris incisa, Epilobium con- 

 fertifolium, Nertera depressa, Carex appressa, and Polystichum vestitum are usually 

 more or less common. 



(iii.) The Rata Forest. 

 * General. 



Wherever there is sufficient shelter to permit tree-growth there is usually a 

 belt of trees round the shore. Within Carnley Harbour, Port Ross, and the inlets 

 of the east coast there is nearly everywhere a continuous forest-mass extending 

 for a varying distance up the hills. On the east of the main island, facing the actual 

 sea, is also a certain amount of forest-growth. 



The trees vary in size according to the degree of exposure, so that in many 

 places the forest is little more than scrub, while in others the roof may be from 6 m. 

 to 12 m. above the ground. Near the shore the formation frequently comes to the 

 margins of the cliffs o:r to the stony shore, while its upper portion, at a height of 

 some 150 m., gradually gives place to scrub. 



** Composition. 

 The rata forest consists chiefly of the following species : Trees — Metrosideros 

 lucida (Myrtaceae) ; Dracophyllum longifolium (Epacridaceae) ; Nothopanax simplex 

 (Araliaceae). Shrubs — Coprosma foetidissima, C. ciliata, C. parviflora, C. cuneata 

 {Rubiaceae) ; Suttonia divaricata (Myrsinaceae). Ferns — Polystichum vestitum, 

 Polypodium diversifolium, Blechnum durum, Asplenium obtusatum, Hymenophyllum 

 multifidum, and a number of other species of the same genus. Mosses — Dicranoloma 

 Billardieri, D. Memiesii, D. setosum, Campylopus introflexus, Macromitrium longi- 

 rostre, Leptostomum gracile, Rhizogonium bifarium, Breutelia pendula, B. comosa, 

 Ptychomnium aciculare, Lembophyllum cochlearifolium, Distichophyllum pulchellum, 

 Cyathopfiarum bulbosum, Campylium relaxum, Stereodon chrysogaster, Acrocladium 

 chlamydophyllum, Mniodendron comosum, M. Kroneanum, M. Sieberi, M. arbuscula. 



