viii FLORA OF NEW ZEALAND. 
or axioms; and they shall have the advantage of being simple, intelligible, and as little exposed to 
the charge of being speculative, as any of that nature can be. I shall assume then— 
$ 1. That all the individuals of a species (as I attempt to confine the term) have proceeded 
from one parent (or pair), and that they retain their distinctive (specific) characters. 
$ 2. That species vary more than is generally admitted to be the case. 
$ 3. That they are also much more widely distributed than is usually supposed. 
$ 4. That their distribution has been effected by natural causes; but that these are not neces- 
sarily the same as those to which they are now exposed. 
ee 
Although in this Flora I have proceeded on the assumption that species, however they originated 
or were created, have been handed down to us as such, and that all the individuals of a unisexual 
plant have proceeded from one individual, and all of a bisexual from a single pair, I wish it to be 
distinctly understood that I do not put this forward intending it to be interpreted into an avowal of 
the adoption of a fixed or unalterable opinion on my part. Whether or not such a theory be con- 
sonant with that great mystery, the origin of organic beings, animate and inanimate, is not the point 
I would here dwell upon; but the fact that it appears to me essential that the systematist should 
keep some such definite idea constantly before him, to give unity to his design, and to guide him in 
the more or less arbitrary restriction of the species of a variable genus, to which he is unfortunately 
often obliged to resort. Except he act upon the idea that for practical purposes at any rate species 
are constant, he can never hope to give that precision to his characters of organs and functions which 
is necessary to render his descriptions useful to others; for in groups where the limits of species 
cannot be traced (or, what amounts to the same thing in the opinion of many, where they do not 
exist), the object of the systematist is the same as in groups where they are obvious,—to throw their 
forms into a natural arrangement, and to indicate them by tangible characters, whose value is approxi- 
mately relative to what prevails in genera where the limitation of species is more apparent. 
In the present imperfect state of our knowledge of the botany of any large area, we have not 
the materials for solving the great questions as to the origin and permanence of species, upon 
general principles. A careful comparative study of the Floras of temperate North America and 
Europe, or of any similarly extensive countries, would throw great light on this subject; or a study 
of the variations of those plants (and they are not a few) which are common to the five great divisions 
of the globe. But these branches of botany are so neglected, that I am not acquainted with a British* 
or Continental Flora, which attempts to give a general view of the variation and distribution of the 
species described in it. I have to some extent attempted this for the New Zealand Flora; but it would 
have been manifestly impossible to have concluded this work within a reasonable time, had I made a 
* In Mr. Hewett Watson's ‘Outlines of the Geographical Distribution of British Plants, and ‘Cybele Bri- 
tannica,’ will be found, amongst a mass of valuable information respecting the Flora of the British Isles, the only de- 
tailed account of the distribution of species within our own shores, and (in the first-mentioned work) a sketch of their 
dispersion over the globe as far as was then known. I am given to understand that Mr. Watson is still engaged on 
the subject, and most sincerely hope that he is so. A more important desideratum to the British Flora cannot be 
named, nor one that would tend more to give that direction to the studies of our local botanists, which is so 
grievously wanted: leading them to the investigation of species as members ofthe vegetable kingdom, and not as 
inhabitants of the British Isles only. 
CEEE E 
