238 The Plant Formations of the High Mountains. 
2. Special Details. 
- @. The Dry Mountains of the South Island. 
Viewed from a lofty eminence in the North-eastern district, grey mountain 
slopes in all directions meet the eye apparently quite devoid of vegetation, 
indeed nothing could appear more desert-like. To be sure, not all the dry 
mountains look so barren as the above, but they rarely possess anything like 
a continuous covering throughout the alpine belt, but show, at best, vast 
debris-fields divided by narrow triangular lines or strips of vegetation which 
converge towards the brown steppe or dark forest. Such lines, or patches, 
raised slightiy above the general level stand out from the dest of unstable 
stones. A closer view shows that there is rarely a continuous plant-covering. 
Patches of clayey, stony soil, large or small, abound containing some times 
the remains of NE plants the long roots exposed, but rarely in process of 
occupation. 
The soil is of diverse origin and may be stones merely (e. g. consolidated 
shingle-slip), loess, glacier-clay or clay from underlying rock. It is obvious, 
that through unstability of the substratum, these must frequently be mixed 
together. As plant-colonization proceeds, a variable amount of humus accu- 
mulates and the soil becomes loamy. The water-content varies much according. 
to the season of the year and to position with regard to the sun, a certain 
average of shade favouring ee vegetation, if the number of rainy days be 
sufficient. 
The most er physiognomic plants are, — certain shrubs (especially 
DröätradE Podocarpus nivalis and low bushes of er uniflorum), flat 
low cushions of several species of Celmisia (€. discolor agg., C. intermedia, 
C. spectabilis and C. viscosa), tall erect rosettes of other species of that genus 
(€. Zyallüi, C. pseudo-Lyallii), tussock-grasses (Danthonia Javescens, D. Raoulii) 
‚ and the Yueca-like Aciphylla Colensoi. The Dracophyllum gives a brownish 
colour to the hillside at an elevation of from 9— 1200 m, and is conspicuous 
from a considerable distance. Podocarpus nivalis forms yellowish mats several 
square metres in extent; it is an early comer and ch characteristic of the most 
exposed stony ground subject to full insolation and violent winds. The leafless 
 yellowish, trailing shrub Erocarpus Bidwillii, \ow dark cushions of the divari- 
cating-shrub Aymenanthera dentata var. alpina (Fig. 74), small hard-leaved 
plants ‘of Gaultheria rupestris and the glaucous-leaved species of Veronica, 
with prostrate gnarled black stems and imbricating leaves crowded near the 
ends of the branches, are all plants of particularly dry and exposed stations. 
Other shrubs of dry ground are: — Carmichaelia Monroi (forming open, low 
 cushions of short, broad, leafless, rigid, flat stems) Styphelia Colensoi (dark- 
 coloured. mats), prostrate Dracopkylium rosmarinifolium. On certain moun- 
. tains from. the North-eastern to the North Otago district is the Semarkable; ’ 
Corallospartium crassicaule, an intensely xerophytic shrub with a stout, r 
re ice en stem, u: mor more er and about : 2 cm 
