170 



wliich it is found. The causes of variation in the northern part of New 

 Zealand, at any rate, are strictly local. At Mount Camel, he states that it is 

 found in a peculiarly dwarf and stunted condition — the same condition is 

 found still further north, and, contrary to the theory which he appears to 

 support, in many localities to the south also. But on the other hand, there 

 are luxuriant specimens, twenty feet high, to be seen at Spirits' Bay in the 

 extreme north, which is equally opposed to the theory. At Whangarei, and 

 at Omaha, the tree attains a height of thirty feet, while one hundred miles 

 south of Whangarei it is seen in abundance, only a few inches in height, 

 growing in great luxuriance, and producing well-developed large sized 

 fruit. 



In New Zealand this plant attains its extreme southern limit, and ought 

 therefore, if the theory be worth anything whatever, to present generally a 

 considerable amount of variation from its ustial forms in Australia, America, and 

 India ; but the very opposite is the case, the variations in the New Zealand plant 

 are simply in size and luxuriance, caused evidently by the nature of its habitat as 

 to soil and shelter. In shape of foliage and fruit it is remarkably uniform, never 

 producing the pinnate leaves and partially-developed fruit which, even in 

 Australia, are not uncommon. Exposed to the full force of the wind on a 

 sandy soil, the plant becomes stunted, the branches numerous, short and 

 weak, the leaves small and short-lived ; old specimens are frequently laden 

 with twiggy branches, few of which are capable of developing even a solitary 

 leaf. In sheltered woods on a good soil, it reaches its highest degree of 

 development, attaining the height of twenty to thirty feet, with luxuriant 

 foliage. Again, when growing on basaltic rocks the plant becomes extremely 

 dwarf, often less than a foot in height, but not stunted, with the foliage and 

 fruit as luxuriant as in the large sylvestral form. The causes of these 

 departures from the luxuriant type are not far to seek. In the first form the 

 growth of the plant is prevented by poor soil and the action of the wind, at 

 the same time the bark and leaves are prevented from exercising their functions 

 by the sand with which, from their viscidity, they are more or less covered. 

 On the rocky soil the plant is dwarf from lack of nutritive matter for the 

 roots, but is still luxixriant from a two-fold cause — the comminuted state of 

 the limited amount of soil allowing the ready extraction of the nutritive 

 matters it contains, and the unimpeded action of the leaves. 



It must however be obvious, that the term variation has a very restricted 

 meaning when applied to mere difi"erences of stature and luxuriance of growth, 

 as in the preceding observations, where the instances discussed belong to simple 

 depauperation, and have no necessary connection with the wide subject of 

 morphological variation. 



In the present state of our knowledge of the subject, a classified statement 

 of the plants which exhibit aberration from their typical forms, with their 



