122 Transactions. — Botany. 



region. Such close growth of branches is carried to its ex- 

 treme hinit in Raoulia eximia (Plates XI., XII.), an inhabitant 

 of rocks facing north and north-west in the alpine regions, 

 whose branches are so close that they form a compact coral- 

 like mass, upon which one can sit down without affecting its 

 shape in the slightest degree. 



Excessive transpiration is also combated in many plants 

 by reduction of their leaf-surface, the most obvious method of 

 which is by reducing the size and number of the leaves. 

 This is carried to such a pitch that some plants have few or 

 no leaves at all. Among the most common are the Carmi- 

 chaelias of this region, whose assimilating functions, &c., are 

 performed entirely by the stems, in which a mdst excessive 

 stereome tissue produces great inflexibility and wind-resisting 

 power. 



Another very common method of avoiding rather than 

 combating the wind is low or prostrate growth, a very com- 

 mon feature in the alpine region, and seen in the lowland 

 and lower mountain region amongst the Carmichaclias, with 

 stiff, erect, leafless branches 2 cm. or 3 cm. high, which form 

 large patches on the stony ground, or in the trailing, almost 

 leafless Muhlenbeckia cphedrioides, or, most of all, in the moss- 

 like river-bed Baoulias — a most efficacious method, since it is 

 well known that the force of the wind is much stronger at 

 some distance from than close to the ground. 



Plants covered with dense masses or mats of hair are 

 frequent, by which not only transpiration but extreme tem- 

 peratures are guarded against. Such plants are especially 

 characteristic of the alpine or subalpine region. Compare, 

 e.g., Craspedia alpina of the shingle-slips, quite snow-white 

 with its thick covering of woolly hairs, with its much less 

 hairy relative C. fimhriata, var., of lowland swamps, or with 

 its thin-leaved almost hygrophilous relative of the west. 



Numerous grasses have rolled leaves. Other plants have 

 the leaves incurved or recurved, all methods for reducing leaf- 

 surface. But I will enter into no more details now, except 

 to point out that Diels was much struck with the extreme 

 xerophilous character of many plants, which he considered 

 out of all proportion to any severity of climate they have 

 now to endure, for, according to him, at the present time 

 the driest regions of New Zealand are less arid and 

 possess a more equable climate than middle Europe — 

 " dass selbst die trockensten Stricbe Neuseelands unter 

 minder excessivem Klima und seltener Diirren leiden als 

 Mitteleuropa " {loc. cit., p. 247); and so he considered Car- 

 michaclia, Hyvienanthera, Corokia, and some others to be 

 descendants of a forest flora which had been forced to retreat 

 northwards during a rising of the land which led to the 



