194 SUBANTARCTIC ISLANDS OP NEW ZEALAND. [Ecnhijical liatanij. 



tion of a clear but boisterous day. That roots are specially developed in a saturated 

 atmosphere was well illustrated by certain whipcord Veronicas which I cultivated 

 in a moist chamber, and which put forth numerous positively geotropic roots from 

 the upper branches, some penetrating the ground.* 



The prostrate habit of the trunks is evidently caused by the constant wind 

 exerting a pressure upon the crown of the tree greater than the trunk can support. 

 On the west coast of Wellington Province, willows exposed to the gales exhibit a 

 similar form. At the same time, there is some evidence in the case of Olearia Lt/nUii 

 that the above habit is more or less hereditary, since quite young seedlings growing 

 within the shelter of the forest have very frequently the stems prostrate for more 

 than half their length. 



DnicopJ/i/IluDi lon<jlfoliuiii and Nofhopanar si)iiplej- have frequently compara- 

 tively short trunks, more or less erect, which are generally much branched from the 

 base. But, perhaps, on the whole they are more treelike than is usually the case 

 in the other floristic provinces. 



The leaves of the trees are thick, coriaceous, stiff (except in S. Stewartine), and 

 glossy (except in D. longi folium). Those of Olearia Lyallii and Senecio Stewartiae 

 are much the largest, these being about 20 cm. by 13 cm., and 18 cm. by 4-5 cm. 

 respectively ; also, they are closely covered with tomentum on the under-surface, 

 that of 0. Lyallii being flannelly and thick. Tliis covering not only checks trans- 

 piration, and permits a large leaf-surface under strong xerophytic conditions, but 

 it protects the closely rolled leaf-buds. The leaves of 0. Li/allii are further provided 

 with a covering of tomentum on their upper surface wlien young, and when first 

 unrolled are white and soft like a piece of flannel. 



The dimensions of the leaves of the other forest-trees are as follows : 5 cm. by 

 1-9 cm. (M. lucida), from 6-5 cm. by 2 cm. to 10-5 cm. by 3 cm. (Nothopanax simplex), 

 16 cm. by 3 mm. (Dracophyllum longifolium). The last named has long, narrow, 

 linear leaves tapering to a fine point, sheathing at the base, concave on the upper 

 surface, and bunched together, 15 or more, the sheaths closely overlapping, and borne 

 at the apices of the ultimate branchlets, after the manner of a tufted grass. They 

 are usually vertical or semi-vertical, and through their arrangement the inner leaves 

 are much sheltered. This strongly xerophytic form and arrangement leads to D. 

 longifolium. occupying the exposed seaward position in a rata forest, or to its being 

 a member of the mountain-meadow formation, where the less xerophytic members 

 are confined to the sheltered gullies. 



{(i.) Shrubs. 



The shrubs are twelve in number. Two [Veronica elliptica and Coprosma 

 foetidissima) not infrequently attain the size of trees, and Inive a distinct trunk. 

 The divaricating form, so common in New Zealand generally, is the most important 

 physiognomically. This consists of a close growth of stiff, interlacing branches, 

 which are given off at more or less of a right angle, the whole forming flattened or 

 rounded bushes of the most extreme density. Tlie leaves are small, thick, cori- 

 aceous, and confined to the periphery of the plant. The life-form is a strongly 



* " On the Seedling Forms of New Zealand Phanerogams " ; Trans. N.Z. Inst., vol. xxxiii, 

 p. 291 ; 1901. 



