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accumulated, and a close covering of ferns, Uncinia australis, and woody lianes has resulted. These forest shingle-slips have originated from the weathering of the rock above, aided by the excessive steepness of the hillsides. The above steepness is another factor which must be considered in connection with the stony nature of the ground, since the two in combination, aided moreover by the deep gullies, lead to a natural system of the most perfect drainage, and provide a very dry station for the plants. How far these debris slopes have been increased or caused in certain cases by the introduced mammals I cannot say, but it is obvious that such must loosen the stones and add in many instances to these slopes, which probably are now of much greater extent than on virgin Kapiti. All the same, it seems more than probable that such slopes have always existed, and it may be possible that they had their origin in the days when the present summits were much higher than now, and when the North and South Islands of New Zealand formed one whole. The soil of the forest is of a dry and not especially fertile character, since it contains usually, and especially at the low levels, but little humus. This may be accounted for by the general dry condition of the forest-floor, which is not favourable to the forming of humus. Quantities of dead leaves are frequently present, but they do not turn into leaf-mould, as in an ordinary rain-forest, but simply dry up, the vascular bundles alone remaining as " skeleton leaves." All the same, humus is not everywhere absent, and in some of the moister gullies and at the higher levels it is more or less abundant. The reaction of one plant upon another must be a matter of much importance with regard to plantdistribution, but it has as yet been little studied in any part of the world, so far as the higher plants are concerned. That certain plants can exist side by side or under peculiar circumstances may sometimes be explained by reference to their special adaptations, but in many cases the explanation is by no means so obvious, and may be beyond the present scope of knowledge. There seems, for instance, no reason at all why the trees of the coastal portion of the forest should tolerate that position while others do not occur in such a place. Paratrophis heterophylla, the milk-tree, is frequent inland in both islands of New Zealand, and yet the closely allied P. banksii is essentially a coastal plant, but so far as xerophytic adaptations go the former species would seem more suitable for the coast. That Corynocarpus laevigata, Myoporum Iwlum, Macropiper excelsum, and Urtica ferox should grow close to the sea remains to be explained. The density of the forest-roof, regulating as it does the intensity of light, has a direct bearing upon plant-distribution, and the Kapiti forest affords one or two interesting examples. Thus, where the original forest was cut down, not far from the landing at Rangitira, a dense growth of Myoporum Icetum has sprung up. The trees are now fully grown. Now, Myoporum Icetum is a tree of a rather straggling habit, and much less close in its foliage than Corynocarpus laevigata, or even the average forest-roof. The consequence is that beneath the Myoporum is a rich undergrowth of seedlings and ferns, notwithstanding the fact that the piece of rejuvenated forest in question is quite unprotected from the incursions of the numerous sheep and the cattle of the neighbouring flat. A second example will suffice. On the spur leading up the slope on the left-hand bank of the Kahikatea Stream is a rather open piece of low forest, its opennees depending on the presence of Pseudopanax crassifolium, Noihopanax arboreum, Olearia cunninghamii, Beilschmiedia tawa, Bysoxylum spectabile, Pittosporum tenuifolium, P. eugenioides, Rapanea urvillei, and Myoporum Icetum. Here the ground is completely covered with vegetation. In some places Uncinia australis is dominant, and almost excludes all else; in other places there is a most abundant undergrowth of Brachyglottis repanda and Olearia cunninghamii, such young trees hiding the low tree-trunks and giving the characteristic stamp to this part of the forest, this special physiognomy being directly due to a brighter illumination than is generally the case in the Kapiti forest, where the tree-tops are closer together and Corynocarpus Imvigata is present. (f.) Distribution and Grouping of the Species. As pointed out above, the forest changes, so far as its species and their grouping is concerned, at different altitudes, and under different conditions; and these latter, as has also been shown, are dependent upon the nature of the ground and the light as regulated by the forest-roof itself. Close to the sea, in some instances hanging right over the upper shore, is a distinct assemblage of plants consisting of the naupata (Coprosma baueri) and the ngaio (Myoporum Icetum), in front or just under which is frequently a line of the tall shrubby nettle (Urtica ferox), a plant with very thin rather pale-green flat ovate-lanceolate leaves, and with many long pale stinging hairs on their petioles more especially. A few feet further from the sea are the karaka (Corynocarpus laevigata), the coastal daisytree (Olearia forsteri), the kawakawa (Macropiper excelsum), the large-leaved milk-tree (Paratrophis banksii), and the mahoe (Melicytus ramiflorus). To this same belt, but rather further from the sea as a rule, belong the kohekohe (Bysoxylum spectabile), the porokaiwhiri (Hedycarya arborea), the forest daisy-tree (Olearia cunninghamii), and the lancewood (Pseudopanax crassifolia). With the exception of Coprosma baueri, Urtica ferox, and Paratrophis banksii, the whole of these plants continue as common representatives of the forest for some hundreds of feet, but they are reinforced by certain other species, and in consequence diminish in numbers. Amongst such species are the tarata (Pittosporum eugenioides), the kohuhu (P. tenuifolium), the mapau (Rapanea urvillei), the rewarewa (Knightia excelsa), the pukapuka (Brachyglottis repanda), the wharangi (Mdicope ternata), the kaikomako (Pennantia corymbosa), the native fuchsia (Fuchsia excorticata), the nikau (Rhopalostylis sapida), the whauwhaupaku (Noihopanax arboreum), the kanono • (Coprosma grandifolia). The ferns, lianes, and herbaceous plants are not mentioned, as they have been dealt with more or less fully earlier on. The upper forest is distinguished by the absence of some of the coastal trees and by the presence of other plants not gen srally occurring at the lower levels, or, if present, then in much smaller numbers.

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