Cockayne. — Observations on Coastal Vegetation. 335 



they increase rapidly. Indeed, vegetative reproduction of this 

 kind is frequent amongst coastal plants, and is manifestly of 

 advantage to the denizens of wind - swept, barren stations. 

 Certain shrubs have the cricoid habit ; others have leaves 

 clothed below with dense tomentum. Pimelea arenaria has 

 small leaves closely covered with white silky hairs. 



The twiggy, divaricating habit of growth so characteristic 

 of New Zealand, and which bears every mark of having been 

 evolved in a region of frequent winds of long duration, is shown 

 in Coprosma acerosa arenaria of the dunes, Plagianthus divari- 

 catus of tlie salt marsh, and Hywenanihera crassijolia of rocks. 

 This latter has much thicker and stiffer branches than is usual 

 in this class of plants. 



None of the shrubs lose their leaves in winter except Plag. 

 divaricatus, whirh is practically deciduous, though in some 

 localities a few leaves remain in the interior of the bush. Some 

 of the salt-meadow and salt-marsh herbaceous plants have their 

 leaves in part or altogether destroyed during the winter, and 

 so late as early September a salt meadow in Canterbury looks 

 as if burnt up by drought. 



The thre^' ferns are evergreen, and have coriaceous leaves,, 

 though those of Lomaria banksii are not strongly so. Lomaria 

 dura and Asplenium obtusatmn frequently develop short trimks. 



The grasses are of the " steppe " character, excepting Cala- 

 magrostis billardieri and Bromus arenarius, both of which have 

 thin, flat leaves. Atropis stricta has a ring of dead leaf-sheaths 

 at the base of its leaves, as in many New Zealand inland grasses 

 and those of deserts. Senecio rotundifolius ond Olearia operina 

 and its close relative 0. angnstifolia ha\e extremely coriaceous 

 leaves, and are in habit like shrubs of the subalpine region. 

 So, too, are Aciphijlla latifolia and A. lyallii ecologically equi- 

 valent to subalpine meadow plants. 



The roots of the psammaphytes and rock plants are long^ 

 those of the salt marsh and salt meadow of medium size or even 

 short. Plagianthus divaricatus has long horizontal roots, thus 

 recalling those of the mangrove Avicennia officinalis, and growing 

 in a somewhat similar station at times. When it grows in firm 

 ground it still has roots of the same kind. The subantarctic 

 " trunk-forming " habit such as we see in Carex secta is oc- 

 casionally to be found in Leptocarpus simplex. Such " tnmks "" 

 are not living structures, but are made up of dead roots and 

 rhizomes, and are an excellent contrivance for raising a plant 

 out of excess of water. 



Stilbocarpa lyallii belongs to a class to itself, since one plant 

 can extend over many square metres of ground by means o£ 



