236 The Plant Formations of the High Mountains. 
siuscula. Where there is a little open ground a few fell-field species, e. g. — 
Pimelea Lyalliivar., Veronica lycopodioides, Aciphylla Monroi, Celmisia laricifolia 
&c., may be present, but are not really a part of the association. 
c. Fell-Field. 
ı. General. 
Fell-field is found in the upper subalpine and alpine belts, its greatest 
development being on the dry greywacke mountains of the South Island. The 
vegetation is always open, the area of bare ground, — stony, clayey or sandy—, 
being frequently much greater than that occupied by plants. Although apparently 
a strictiy edaphic formation, yet the requisite substratum can only be formed 
in a climate favourable for the disintegration of rock and soil, while such a 
re is unfavourable for all plants except more or less ne xerophytes. 
disintegration constantly in progress renders the formation far from 
tongiircn, the vegetation being in a constant state of destruction and renewal. 
A heavy snowfall is before all else the most powerful factor for damage, on 
a large scale, since it leads to snow avalanches which tear up the surface 
destroying all vegetation and depositing the remains on the gully-floor hun- 
 dreds of metres below. Further, in the struggle between climate and plant- 
Re colonization, the former has now most powerful allies in the shepherd’s fires 
er ae beepr together with the rabbit-pest and the various animals introduced “ 
” purposes. Seeds germinate well enough, when they get the chance, 
% Br in New erg at any rate it is not as WARMING suggests (1909: 256) a 
N relation seed-germination ‚and climate that determines the Opean 
Yo of felkhield, bu altogether the disintegration factor. 
} ; the ecological conditions resemble hole of shingle-slip, 
i bar there, is the great distinction ot temporary stability of the substratum. 
 Probably t water-content of the soil is less, especially where clayey. There 
rel Bee flat places and hollows, where snow collects, and in such, 
 . owing to the better a N are oases of closed vegetation, some of 
A whose. species do not occur on fell-field proper. Large stones and 
common feature (ig. 73), afford shelter and shade, and supply a sp 
station. ‚So ‚too, - here fs streams, or De where water oozes | 
