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Coniferse ; such plants are found equally abundant and luxuriant in the north, 

 as in the extreme south. 



Others again find their northern limits before reaching the North Cape 

 district, or dwindle in size from the locality of their maximum growth in the 

 South Island. Of such are some of the Pittosporums, Leptospermum ericoides, 

 and L. scoparium, Fuchsia excorticata, Griselinia littoralis, Drimys axillaris, 

 and D. Golorata. 



The birch forests (Fagus), which are so important in the South, are also 

 absent from the North, a few stragglers only being found on the line of the 

 main ranges. 



In the district under notice, frequent instances may be found of that 

 disposition to vary, so common among New Zealand species of plants, the cause 

 of which by some has been ascribed to the whole Flora having arrived at such a 

 delicate state of balance, that any small disturbance would produce a great 

 change ; but I think it more probable that causes of change have always been in 

 operation while a Flora existed in the islands ; and if the range of latitude, and 

 thermal variations which must exist over such a range be considered, it will 

 only require the transportation of plants from localities well suited to them, 

 and vice versa, to produce some variation of form, as we see. 



As might be expected, arid winds seem to exert a stronger influence, in 

 producing plant variation, than even temperature. For instance, at the North 

 Cape, and Cape Maria "Van Diemen, species such as Myoporum, Icetum, 

 Goprosma acerosa, and others, even under the dry warm winds of that 

 latitude, may be seen dwarfed and stunted, flattened out on the ground, and 

 hiding themselves, as it were, behind the sand-hills. The same may be seen at 

 Mount Camel, where large patches of low copse forest of the Akerautangi 

 (Dodoncea viscosa) cover the ground, whereas the same plant at Nelson, 7° of 

 latitude further south, forms a handsome, though small tree. In these cases 

 where the causes to variation are not so evident and direct as the action of 

 arid winds, it would appear that the tendency of a plant to vary is increased 

 with the distance from its centre of maximum growth* 



I am inclined to the opinion that variation in some species shows its 

 derivative track by the young plants reverting to some older type form. As 

 an instance of this, Weinmannia Sylvicola is often seen, in the young state, 

 dotted over the open Kauri gum. land, having only imparipinnate leaves, while 

 the older tree assumes a ternate form in the upper branches ; and in full adult 

 trees, the foliage becomes unifoliolate in the upper branches, and ternate in 

 the lower — thus, I infer, showing the typical foliage of two species now extinct. 

 It is even probable that the above species has passed through one form, that 

 still exists in the South, Weinmannia racemosa, which also shows the extinct 

 form of ternate leaves, but only in the young plant and lower branches. 



The limits of this paper will not allow further illustrations of this curious 

 point, although there might be many added with facility. Local collectors 

 will always be liable, in New Zealand, which possesses such a varying Flora, to 

 be deceived with supposed new discoveries, and may be frequently puzzled, 

 from the descriptions in Hooker's "Handbook" having been frequently taken 

 from specimens found only in one locality. Thus, no southern collector has 



*As illustrative of the influence of humidity or aridity on plant variation, the Kowhai 

 (Sophora tetraptera) may be taken as an example. Near Dunedin it may be said to have 

 acquired its maximum of growth, under the conditions of excess of cold humid winds. 

 On the west coast of the South Island, again, under conditions of warm humid winds, 

 it is a delicate drooping branched shrub-tree, while on the seaward grass hills of Marl- 

 borough, under the conditions of an arid cold wind, the same plant has become dwarfed 

 to a few inches high, covering patches of ground, and rigid enough to be walked on ; 

 temperature here shows the least influence, as otherwise the West Coast variety would 

 have been the largest. 



