226 SUBANTARCTIC ISLANDS OF NEW ZEALAND. [Ecological Botani/. 



divaricaia and Cassinia Vauvilliersn rise above the Carex tussock. Other plants 

 noted were Hierochloe Brunonis, Carpha alpina, Bulbinella Rossii, Blechnum capense, 

 and Cdmisia vernicosa of loose habit of growth. 



Near streams and in wet ground in Danthonia meadow may be Polystichum 

 vestUum, almost pure or in company with Poa litorosa and Carex appressa. 



***Bogs. 



The bogs owe their physiognomy to the cushion form, as exemplified in the 

 stiff cushions of Oreobolus pectinatus, the hard green ones of Phyllachne davigera, and 

 the circular soft ones of Gaimardia ciliata. Astdia suhnlata, spreading far vegeta- 

 tively, makes a kind of turf, as does the rather taller Astdia linearis and the far- 

 spreading Coprosma repens. 



The small Drosera stenopetala is here and there, and there are occasional plants 

 of the strongly xerophytic small fern Schizaea fistulosa var. nustralis, its rushlike, 

 slender fronds, 9 cm. tall or less, given off from a rather thick rhizome, and crowded 

 together. Certain of the meadow plants will be present, especially Btdbindla Rossii, 

 Coprosma repens, and Cdmisia vernicosa. In fact, it is hard to say where meadow 

 begins or bog ends, much of the former being semi-bog, and perhaps the bog is best 

 defined by the presence of an abundance of cushion plants, especially of Phyllachne 

 davigera, whose cushions, bright green at one season and at another begemmed 

 with multitudes of pure-white flowers, are very striking (see fig. 5, p. 196). 



At lower levels, sometimes at sea-level, and also forming open spaces amongst 

 the moimtain scrub or following the bank of a creek, are bogs or swamps where the 

 ground is sopping wet, and there is a close growth of Carex appressa, while growing 

 through this are usually many fine specimens of Stilbocarpa polaris and especially 

 Pleurophyllum criniferum. Blechnum capense is also abundant. In places the vege- 

 tation is 1 m. in depth. The Stilbocarpa forms close green patches, contrasting 

 with the dull-coloured fern or straw-coloured Carex, and the huge pale-green Pleuro- 

 phyllum leaves stand out above the whole. Where there is less water the Carex is 

 reduced in quantity and the Pleurophyllum much increased. 



From the above paragraphs it may be seen that bog is rather more xerophytic 

 than tussock meadow, and that the selective power of the substratum increases in 

 proportion to increase in its water-content. 



(xii.) Subalpine Rocks. 



It is usually only near the shore and on the actual summits of the hills that 

 rock crops out. Crevices and hollows are generally filled with peat, or this may cover 

 the entire surface. On the bare rock is the fme suffruticose lichen Stereocaulon 

 ramulosum and several crustaceous species. Here also are black patches of the 

 small mosses Andreaea suhulata, A. nitida, and A. mutahilis. The chasmophytes are 

 the creeping Azordla reniformis, the small cushions of the needle-leaved Colohanthus 

 subulatus, Geum alhiflorum, Cardamine depressa, C. glacialis var. suhcarnosa. Poly- 

 podium pumilum and Hymenophyllum multifidum form lines in the crevices or 

 extensive sheets on the peaty covering. On wet rocks and on the peat certain 

 mosses are common — e.g., Braunia Humholdtii, Lophiodon stridus, Conostomum 

 australe, Hypnum hispidum. Growing in the largest debris beneath the cliffs is the 



