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Show 456 ISLAND LIFE. (PART II. hypothesi.s , wlu.c h seems necessary t o exp lain the occurre.n ce of so many speci.e s of t 11 ese b1' r d s m· a sma 11 area but of wh10h we h ave no I. n d epend en t proof. Th.e re are ' however, some other facts which would be explained by it, as the presence of. three, pecu 11. ar b ut a llI'e d oO 'enera of starlings ' the. t. hree s.p ecies of parrots of tho genus Nestor, and the six d1stm~t r~Ils of tho genus Ocydromus, as well as the numerous spee1:s m some cf the peculiar New Zealand genera of plants, wh10h seem loss likely to have been developed in a single are~ th~n when isolated, and thus preserved from the counteractmg Influence of intercrossing. In the present state of our knowledge these seem all tbe conclusions we can arrive at from a study of the New Zealand fauna; but as we fortunately possess a very full and accurate knowledo·e of the flora of New Zealand, as well as of that of Australi: and the south temperate lands generally, it will be well to see how far these conclusions are supported by the facts of plant distribution, and what further indications they afford us of the early history of these most interesting countries. This inquiry is of sufficient importance to occupy a separate chapter. CHAPTER XXII. THE FLORA OF NEW ZEALAND : ITS AFFINITIES AND PROBABLE ORIGIN. Relations of the New Zealand Flora to that of Australia-General features of the Australian Flora-The Floras of South-eastern and South-western Australia-Geological explanation of the differences of theso two Floras-The o1·igin of the Australian element in tho Now Zealand Floro. -Tropical character of the New Zealand Flora explained-Species common to New Zealand and Austrnlia mostly temperate forms--Why easily dispersed plants have often restricted ranges-Summary and Conclusion on the New Zealand Flora. ALTHOUGH plants have means of dispersal far exceeding those possessed by animals, yet as a matter of fact comparatively few species are carried for very great distances, and the flora of a country taken as a whole usually affords trustworthy indications of its past history. Plants, too, are more numerous in species than the higher animals, and are almost always better known; their affinities have been more systematically studied; and it may be safely affirmed that no explanation of the origin of the fauna of a country can be sound, which does not also explain, or at least harmonise with, the distribution and relations of its flora. The relations of the flora of New Zealand to that of Australia have long formed an insoluble enigma for botanists. Sir Joseph Hooker, in his most instructive and masterly essay on the flora of Australia, says:-" Under whatever aspect I regard the flora of Australia and of New Zealand, I find all attempts to theorise on the possible causes of their community of feature frustrated by anomalies in distribution, such as I |