HorLowav.—Studies in the New Zealand Hymenophyllaceae. 75 
north-west winds, however, are frequent and drying, and at times very 
fierce. It is apparent, then, that Cass possesses a more severe climate "m 
that which prevails on the eastern flanks of the dividing range. Cockayn 
and Laing have shown (16, p. 345) that these two climates, the biduo 
forest and the tussock-grassland climate, pass into one another without a 
transitional phase, and that the sharply defined line which separates them 
extends throughout Canterbury at a short distance east of the dividing 
range. They add, “ The steppe [2.е., the tussock-grassland] climate is far 
from being really dry, but clear skies wit strong insolation are frequent, 
and the ever-present wind would demand a much higher rainfall before 
forest could establish itself naturally." The following are the annual rain- 
fall figures available with respect to Cass : 1917 (from 21st April), 38°7 in. 
1918, 59°8in.; 1919, 40°6in.; 1920, 43'0in 
accordance with these climatic conditions p viduam beech (N. chif- 
fortioides) forest in the neighbourhood of Cass is present only in patches 
in the mountain-side gullies, the greater part of Tg area eres covered 
by tussock-grass, divaricating shrubs, and subalpine herbs, and the river- 
terraces by mat and cushion plants and by the thorny Discaria toumatou. 
For a fuller account of the plant ecology of this area reference must be made 
to Cockayne and Foweraker (15). The interior of the patches of Notho- 
S 
he 
of Hyme nophyllum еч is Н. villosum, which occurs on the groun 
moss near the creek-sides. Mr. Foweraker ‘informs me that the same species 
is present in a very stunted form on rocks at the summit of Mount Sugar- 
loaf, in the immediate vicinity of Cass, at an altitude of about 4,000 ft. 
their account of the plant ecology of the Mount Arrowsmith district 
(see map 3, on page 76), which lies between the upper Ashburton and 
Rakaia Rivers, a few miles to the east of the boundary of the Western 
Botanical Distriet, Cockayne and Laing (16, p. 357) note the presence at 
subalpine altitudes of H. villosum as a special ae and H. multifidum 
on peaty humus on rock-ledges and in chinks. ockayne informs me 
2 on the wetter mountains of Central Otago n map 4, on page 85) 
multifidum occurs in its mountain form in sheets on shady rocks at 
altitudes of 3,000 ft. and upwards. 
©. The Eastern Outlying Mountains of Canterbury. 
From map 3, on page 76, it will readily be seen that separating the 
intermediate montane area of Canterbury from the eastern plains there 
is a chain of high nde separated from one another by the main river- 
valleys. These outliers are forest-clad on their seaward slopes. I pro- 
pose now to give à оя of the distribution of the Hymenophyllaceae 
in the forests of three of these outliers—viz., Mount Oxford in the north, 
Mount Peel and Mount Studholme in the south—adding also what is 
known as to their occurrence in the original forests of Banks Peninsula. 
As has already been mentioned, the presence of continuous forest on 
the eastward slopes of these outliers, which in the case of South Canter- 
bury, and also of Banks Peninsula, must be reckoned rain forest, is due 
to the easterly and сг degere in addition to the occasional 
north-west showers. е ћете drying nature of the north-west winds 
is experienced rather in the ether than in the extreme southern parts 
of Canterbury. І am informed by Mr. Е. Akhurst, the meteorological 
