vni 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 th a t 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 th a t they retain their distinctive (specific) characters.
§ 3. That species vaiy more than is generally admitted to be the case.
§ 3. That they are also much more widely distributed than is nsnally supposed.
§ 4. That their distribution has been effected by natiu'al causes; hut th a t these are not necessaiily
the same as those to which they are now exposed.
Although in this Flora I have proceeded on the assumption th a t species, however they originated
or were created, have been handed down to us as such, and th a t all the individuals of a unisexual
plant have proceeded fi-om one individual, and all of a bisexual from a single pan, I wish it to he
distinctly understood th a t I do not put this forward intending it to he interpreted into an avowal of
the adoption of a fixed or unalterable opinion on my part. Whether or not such a theory be consonant
with th a t great mystery, the origin of organic beings, animate and inanimate, is not the point
I would here dwell upon; but the fact tha t it appears to me essential th a t the systematist should
keep some such definite idea constantly before him, to give unity to his design, and to guide liim in
the more or less ai'bitrary restriction of the species of a variable genus, to which ho is unfortunately
often obliged to resort. Except he act upon the idea th a t for practical purposes a t any rate species
are constant, he can never hope to give th a t 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 natm-al arrangement, and to indicate them by tangible characters, whose value is approximately
relative to what prevails in genera where the limitation of speeies is more apparent.
In the present imperfect state of our knowledge of the botany of any large area, we have not
the materials for solring the great questions as to the origin and permanence of species, upon
general principles. A careful comparative study of the Floras of temperate N orth America and
Europe, or of any similarly extensive countries, would throw great light ou 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, th a t I am not acquainted w ith 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; hut it w'ould
have been manifestly impossible to have concluded this work within a reasonable time, had I made a
* 111 Mr. Hewett Watson’s ‘ Outlines of the Geographical Distribution of British Plants,’ and ‘ Cjhele Bri-
tannica,’ will be found, amongst a mass of valuable information respecting the Flora of the British Isles, the only detailed
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, wlucji is so
grievously wanted; leading them to the investigation of species as members of the vegetable kingdom, and not as
inhabitants of the British Isles only. ’
critical examination of all the forms from alb countries, of those Now Zealand species which are
cosmopolitan; such operations must necessarily be left to my successors, who may receive many of
my remarks on the dispersion of the species simply as suggestions.
A want of materials is not, however, my only reason for withholding a decided assent to the view
I have enunciated. There are other theories which claim more or less consideration from every un prejudiced
naturalist; and there are such theoretical and practical difficulties (and perhaps impossibilities)
in the way of our coming to any conclusions as to the limits of the species of m any genera,
as give colour to the assumption th a t they have no permanently recognizable limits. A statement
of some of these riews and difficulties may ho the means of throwing much light on this subject; and
they are w'ell worthy of the consideration of the New Zealand botanist; for islands situated far from
continents, and in the midst of great oceans, offer many favourable points from which to s tart in
such investigations.
1. Very many naturalists consider species as permanently distinct, but demand a plurality ofr
parents to account for their extensive distribution.
3. Another large class do not consider species as permanent at all, and hold th a t what are called
such, are stii-pes or races (like those of man, and such of the lower animals as dogs, horses, etc.),
subject to change or obliteration, which have been either accidentally produced, or developed accord-
ing to some theoretical lair.
3. A third class believe in a progressive development of all organized nature, from the cell to an
ideal type of perfection, towards which man is the last step reached.
4. Others subscribe to various shades of these opinions, or blend them as far as they consistently
can; some, taking even a much larger view of the limits of variability consistent with permanence of
type than I profess to have adopted, think genera of plants permanent types, and species accidentally
produced varieties.
Arguments in fai^our of these views are not wanting, derived both from the animal and vegetable
kingdoms; the chief o f which are drawn from a large class of well established facts, upon the bearings
of which the most distinguished and candid naturalists ai’e divided in opinion : such are—the great
number of genera whose species have baffled aU attempts at circumscription by fixed characters,—
the facility with which breeds of certain plants and animals may be propagated, and the comparative
certainty vdth which some few i^aricties arc reproduced under favourable circumstances,—the great
facility with which many plants hybridize, and the fact of hybrids liaHng proved fertile,—the sudden
appearance and unexplained cause of many varieties or sports,—and the difficulty of accounting for
the existence of idants and animals in two or more localities, between which they cannot have been
transported by natural causes now in operation. These are all questions relating to the diffusion
and variation of species, which will be discussed here and in the following section.
Arguments in favour of the single creation, and permanence of species, are all based upon
general considerations of the phenomena of distribution. Comparative anatomy, which has thrown
such great light upon this branch of study in the sister kingdom, has not done so much for p la n ts ;
tins arises from several causes:—1 . The habits of allied plants do not differ so remarkably as those
of animals, and there is consequently less modification of their functional organs.—2. The relation
of tliese modifications to the habits and wants of the species, is in the animal kingdom directly
appreciable, but in plants no such connection can be traced*.—3. The individual organs of support,
* The structure of woods oilers many illustrations of this; very closely allied plants (especially Lei/tmiinosa)
differing entirely in the nature, arrangement, and development of the vascular and cellular tissues of their trunks.