Cockayne. — Plant Geography of the Waimakariri. 119 



mountain -ranges which bound it and set down both the 

 north-west and the south-west rains. Thus it often rains 

 at Lake Pearson when the higher ground of the Trehssick 

 basin is rainless ; and, again, it may rain on the Canter-- 

 bury Plains and on Mount Torlesse and yet the region 

 under consideration be dry. Perhaps the Trehssick basin 

 bears more resemblance CECologically to Central Otago than 

 to any other region in New Zealand.* 



The Eastern Climatic Plant-region. — The oecological 

 character of this region is essentially xerophilous.f This is 

 not to be wondered at when the small rainfall and constant 

 drying winds in conjunction with the usually stony soil is 

 considered. To be sure, there is much swampy ground, but 

 such to many of its inhabitants is physiologically dry. 

 Schimper writes {loc. cit., p. 4), "In der That ist eiu sehr 

 nasses Substrat fiir die Pflanze vollkommen trocken, wenn sie 

 ihm kein Wasser zu entnehmen vermag, wahrend ein Boden, 

 der uns vollkommen trocken erscheint, manche geniigsame 

 Pflanze hinreichend mit Wasser versorgt. Es muss zwischen 

 physikalischer und physiologischer Trockenheit, bezw. 

 Feuchtigkeit unterschieden werden ; letztere allein kommt 

 fiir das Pflanzenleben, also audi fiir die Pflanzen geographic in 

 Betracht." Diels, in a long list embi'acing plants of varying 

 stations {loc. cit., pp. 216, 217) with regard to moisture, classi- 

 fies them all as hygrophytes, evidently more from their station 

 than from their structure. 



Phormium tenax, e.g., usually a denizen of swamps, occurs 

 also on dry river-terraces, on sand-dunes, and even on dry 

 faces of rock — upper Waimakariri Gorge. Leptocarjms simplex, 

 a curious restiaceous plant, lives equally well either in brackish 

 marshes or on sand-dunes. In cultivation in my garden, on 

 an almost perpendicular rockery, exposed to the full rays of 

 the sun and to the north-west wind, Epilobium macrojnis, 

 whose usual habitat is cold running w^aterin subalpine streams, 

 thrives amazingly, yet receiving exactly the same treatment 

 as Paronychia argcntcal of the Mediterranean region, side by 

 side with the former, and in excellent health. Claytonia 

 australasica grows both in shallow runnmg water and on 

 shingle- slips. 



* The plants of Central Otago are distinguished in Petrie's list by the 

 mark C (Trans. N.Z. Inst., vol. xxviii., 1895, p. 540). 



t Plants of the pine forest and certain marsh plants form an excep- 

 tion to this; also, the New Zealand Fagi are classified by Schimper as 

 tropophytes, on account, I suppose, of the conspicuous young-leaf growth 

 during early spring, and the often deciduous habit of the most exposed 

 branches. 



I Nicholson for this plant recommends a light dry soil : " The Illus- 

 trated Dictionary of Gardening," London, vol. iii., p. 25. 



