Ecological Botany.] 



SUBANTARCTIC ISLANDS OF NEW ZEALAND. 



197 



is increased through the decay of the older branches, &c., which build up a peaty 

 water-holding mass, into which the ultimate leaf-bearing shoots finally root. ^20- 

 rella Sdago, of Macquarie Island, alone assumes those gigantic dimensions which can 

 vie with the species of Raoulia or Haastia of the Southern Alps ; still, the smaller 

 cushions of the following are of considerable density, especially those of the last 

 named, which are quite hard : Gaimardia ciliata (Centrolepidiaceae), Oreobolus pedin- 

 atus (Cyperaceae), Cdobanthus muscoides (Caryophyllaceae), Phyllachne davigera 

 {Stylidiaceae). (Fig. 5.) 



The form under consideration is a distinctly powerful xerophytic adaptation, 

 transpiration not only being reduced to a minimum, but the peaty mass holding a 

 constant water-supply, an " adaptation " analogous to that of succulence in a desert. 

 The permanence of this form is discussed under another head. 



Vui. ti. — Ai-ii'hijUii Utijulia ghowino in Pleiirojihyllum Meai>ow, Ahams Island. 

 Stilbocarpa polurii iu left-lmnd corner, and Polygticluim vestitum in background. 



*** The Large-leaved Form. 

 The possession of large leaves, though a common and most remarkable attribute 

 of certain of the plants, cannot really be considered a life-form, though, as it is one 

 of the most striking features of the vegetation, it is convenient to consider it as such. 

 Here belong all the species of Pleurophyllum, the two species of Stilbocarpa, the three 

 species of Aciphylla (fig. 6), and Btdbinella Rossii. That so many plants can exhibit 



