216 SUBANTARCTIC ISLANDS OP NEW ZEALAND. [Ecological Botany. 



and eventually as an epiphyte. P. Billardieri and P. grammitidis are also frequent 

 epiphytic ferns. The fine foliaceous lichens Sticta Freycinetii, S. filicina, S. orygmaea, 

 and S. fragillimn are abundant on trees, logs, or the ground, lending a special cha- 

 racter to the vegetation. 



In many parts of Adams Island the forest is so low as to be a transition to 

 scrub. My notes say, " There is here little actual forest, the taller arborescent 

 plants being confined to the gullies. The trees are not especially of the wind-swept 

 character ; there is but little undergrowth, and the customary moss or liverwort 

 cushions and mats are wanting on the trunks, while even on the ground are but few. 

 Metrosideros lucida and its associated plants make up the bulk of the forest. Note- 

 worthy is the form of Snitonia divaricata, which has slender twisted naked stems 

 and a flat tablelike top of closely interwoven and twisted wiry twigs. On the floor 

 are many ' needles ' of the Dracophyllum. As the trees are not especially pro- 

 strate, one walks on the ground, not on tree-trunks. In open places is a good deal of 

 Astelia linearis and JJncinia riparia var. Hookeri. Looking at the forest-roof, is to 

 be noted the shining green Metrosideros and the erect yellowish-green Dracophyllum 

 longifolium, the former with a rounded head ; the paler green Coprosma foetidissima 

 and Nothopanax simplex, its shining green leaves tinged with yellow." 



Near the shore Dracophyllum longifolium is frequently a most abundant plant, 

 and it often forms a belt at the forest's outskirts, jutting over the cliffs or the stony 

 shore ; very frequently, indeed, its stems are quite covered with sooty masses of 

 Antennaria scoriadea. Where the forest-roof is for some reason more open, there 

 may be a pure undergrowth of Nothopanax simplex, having numerous stems from 

 the ground. Epilobium confertifolium, Stdlaria decipiens, and Epilohium linnaeoides 

 are common forest herbs, but they play little part in the physiognomy. 



The rata forest is closely related to the forest of Stewart Island near the sea, 

 to portions of the forests of the Sounds of Otago, and to one phase of the subalpine 

 forest of Westland. 



(iv.) Mountain Scrub (Suttonia Formation) (fig. 11).* 



At a variable height above the forest comes the mountain scrub. No hard- 

 and-fast line can be drawn between the two formations, the one merging into the 

 other, while even the principal species are identical, though their proportions are 

 very different, as is also the physiognomy and ecology of the two formations. 



The chief peculiarity of this formation is its astonishing density. The shrubs 

 are so rigid, much-branching, and interlaced that it is frequently quite impossible 

 to force a passage through, or even to crawl beneath them ; the only mode of pro- 

 gression is to roll over their top. 



Suttonia divaricata is dominant, and to this especially is the extreme density 

 owing. Cassinia VauviUiersii is very much commoner than in the forest, and its 

 sage-green colour, or the whitish-yellow of a strongly marked variety, strikingly 

 contrasts with the darker green of the other shrubs. 



According to the exposure, so does the scrub vary in height ; in some places 

 it may be 2 m. tall, or taller, but in others only 1 m. or less, but with a closeness of 

 growth almost incredible. 



* This picture gives no idea of the formation ; unfortunately, no photograph of typical scrub 

 was secured by the expedition. 



