SpKHiiiT, Cockayne, Laino. — Mounf ArmwKinith Diatrict. 363 



C ciliata, C. parviffora. C. rugosa (Rubiac.) ; Olearia nitida, 0. macrodonta, 

 O. ilicifolia, 0. nummularifolia, Cassinia Vauvilliersii, Senecio cassinioides, 

 *S. elaeagnifolius (Comp.). 



*** (rroiclh-formi. 



Tlie " normal " forms of scrub plants are much modified by the 

 mechanical action of wind and snow, and it is to the dwarfing, the horizontal 

 spread of branches, and, above all, the close intermingled groAvth that the 

 scrub maintains its position rather than to any special growth-forms of 

 the constituents. This is admirably shown by the forest-tree Nothofagus 

 cliffortioides, which, like the ecologically equivalent Pinus nwntana of Europe, 

 can assume a scrub form, and so make a special type of subalpine scrub, 

 as in the Nelson mountains. 



Regarding the Rakaia shrubs, all except two are evergreen. The shrub- 

 composite form, the divaricating form, the ball-liJie form, the creeping and 

 rooting form, the husky form, the Dracophyllum form,X are all represented. 

 Nearly all have stiff, coriaceous, or thick leaves. The leaves of six are 

 tomentose ; of two erect, needle-like, isolateral or nearly so ; of nine quite 

 small. In short, with the exception of the deciduous element, Veronica 

 salicifolia and perhaps V. subalpina, the leaf-form and structure is xerophytic 

 or subxerophytic. Clematis australis is a tendril-climber, with much-divided 

 rather thick leaves. The other lianes occur in the scrub of the river-bed. 



{e.) Subalpine Totara Forest. 



* General. 



An association in which the totara [Podocarpus Hallii, and perhaps 

 P. totara also) is the dominant tall tree occupies the base of the mountain- 

 slopes on both sides of the Rakaia Valley, extending on the sunny side 

 to a higher altitude (perhaps 970 m.) than on the shady side. Only the 

 forest on the southern side (sunny side) of the river was examined, it being 

 impossible to ford the river on foot. 



The formation is the same as that composing the upper forest of West- 

 land extending from the Taramakau Valley to the River Paringa, but it 

 differs considerably floristically. 



The association under consideration changes considerably both floristic- 

 ally and ecologically according to altitude, the lower and upper portions 

 ■constituting respectively two subassociations. 



The lower forest contains the following species which are wanting (or 

 rare) in the upper forest : Asplenium flabellifolium, Carpodetus serratus, Pitto- 

 sporum tenuifolium, Sophora microphylla. Fuchsia excorticata, Pseudopanax 

 crassifolium. 



** Upper Fore-it (Totara- Kawaka Suhassociation). 

 t Character. 



The upper forest (see Plate VII, fig. 1) is distinguished by the presence 

 of Libocedrus Bidwillii (kawaka) as a tall tree, in addition to the totara ; 

 by the presence of certain members of the subalpine scrub, which, shrubs no 

 longer, have now the form of small trees ; and, above all, by the generally 

 horizontal trunks of these latter. The floor is covered in most places with a 

 tall growth of the fern Polystichum vestitum. Moss mantles are abundant 

 on the horizontal trunks and branches. 



t Naked stitt' stems, often more or less fastigiate ; leaves long, grasslike, in erect 

 rosettes at the apices of the twigs, and frequently almost isolateral. 



