Page:Transactions and Proceedings of the New Zealand Institute - Volume 1 (2nd ed.).djvu/47

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the plants indigenous to the Middle Island of New Zealand, there are none which range more widely, both in altitude and in latitude, nor which present a greater amount of variation, than the Veronicas. Indeed, as Dr. Hooker remarks, in the notes to the Conspectus of this genus, published in his "Handbook of the New Zealand Flora," so numerous are the intermediate forms between very distinct looking species, as to render the species excessively difficult of discrimination, and to compel the adoption, for the purposes of an interim classification, of purely arbitrary characters founded on "prominent prevalent differences only." Dr. Hooker, in a communication to myself in reference to a large and varied collection of specimens which I forwarded to him in the early part of 1864, whilst he was engaged in compiling the "Handbook," remarked on the possibility that the variation referred to might be due to natural hybridization, and asked me whether I thought this was the case. In reply, I expressed an opinion against the supposition, and the following paper contains the substance of the grounds urged by me against it.

Before, however, entering upon the special question under discussion, I will venture to call attention to the two principal theories now prevalent respecting the origin of the various species of organic life found within particular areas. The first is, that the surface of the globe, at an early period, became divided into a number of great areas of population, each of which contained a distinct fauna and flora, distinguishable by characteristics proper to that particular area only; and that the various species now found within it have from time to time been since created in order to supply the place of representative species which have died out. The second is, that every group of organisms has a purely derivative origin, and that each existing species is but the modified descendant, preserved by means of natural selection, of some other species: whilst, probably, in most cases so great a divergence has taken j)lace from the original type, as to transgress the conventional circle which we draw round generic type, and induce us to refer it to some other genus than that to which it would originally have been assigned. It has been well observed that if the first of these theories be true, all attempts to trace the origin of present and past faunas and floras must necessarily be futile, for their origin would be sufficiently elucidated in the dogma that "they were created on the spot," and that such a theory would render palæontology a useless study, and reduce it to a mere leviathan catalogue of fossils. Notwithstanding, therefore, the "weighty difficulties which surround the theory of natural selection," (as observed by the great