114 NEW ZEALAND PLANTS. 
cold streams; and the silvery cushion-celmisia (Celmisia argentea), 
a species of boggy herb-field. Other examples could be given, 
but these suffice to illustrate the class of plants which have come 
from the heights, or which, it may be, ascended thither from their 
original lowland stations. 
There are two broad paths by which alpine plants can gain the 
lowlands without greatly changing their mode of life: they can 
follow the stony river-beds from their sources far in the heart of the 
mountains or they can descend by means of the tussock-grassland. 
There is thus no need for the alpine plants of such plant-formations 
to choose any means of progression other than the slow one of 
competition with their neighbours—not an uncommon method of 
getting on in the world, after all ! 
The beautiful autumn coloration of leaves exhibited by many 
trees of the Northern Hemisphere cannot be expected in a vegetation 
whose trees are nearly all evergreen. Nevertheless. the high- 
mountain plants of New Zealand show a considerable amount of 
winter coloration, the result of frost. Various evergreen shrubs 
have their leaves thus coloured—e.g., the manuka (Leptospermum 
scopartum), the mountain southern-beech (Nothofagus cliffortioides), 
and the mountain-korokio (Corokia Cotoneaster). The coloration is 
especially striking in bog or river-bed cushion-plants, so that in 
winter a river-bed may be a place of remarkable beauty. The 
most striking feature in this particular are the great cushions of 
Raoulia Haastii of the Waimakarin or Rakaia mountain - valleys, 
which in summer are bright-green, but in winter are of various 
shades of rich chocolate-brown, and are indeed a delightful spectacle. 
Another raoulia (Raowlia tenuicaulis) assumes many colours—e.g., 
yellowish-green, pale reddish-brown, and greys of different tints. The 
case of Pimelea prostrata var. repens is of special interest, since some 
plants are coloured and others in the immediate vicinity undergo 
no change. The green cushions of Donatia novae-zelandiae and 
Phyllachne Colensoi of the high-mountain bogs become more or less 
red in winter. Very few observations regarding winter coloration 
of New Zealand plants have been made, and doubtless many others 
exhibit a distinct winter coloration. It may be pointed out, how- 
ever, it is of just as much importance to observe those species 
which do not colour as those which do so when both are growing 
under apparently identical conditions 
