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Europe*, and tliose highly sportive ; and in the Ilmialaya, the liead-qnartcrs of the genus, tlicrc are
still more species, and those (comparatively speaking) by no means variable. Again, Clemahs,
Ramuicuhts, Epilobium, Apium, Lobelia, IVahlenbergia, Gaultheria, Oka, Gentiana, Calystegia,
Euphrasia, Luzula, and Poa, all very cosmopolitan, are as variable in New Zealand as elsewhere,
and some of them more so ; but as they arc not as equally represented in number of species in New
Zealand as elsewhere, the residts presented by each genus are of ^æry different value. Thus Lobelia
and llahlenbergia, though very large genera indeed in mauy parts of the globe where the species
ai-e not conspicuously protean, ai’e represented in New Zealand by two widely diffused and exceptionally
protean species. Potamogetón and Poa (with many others) belong to a class equally common
in New Zealand aud elsewhere, and equally variable everywhere. Epilobium, Veronica, Senecio,
and others, hcai’ a lai'ger proportion to the New Zealand Flora than to any other Flora of equal area
and number of species, and are decidedly as variable in New Zealand as anywhere.
(c.) I f we tiu'n to the sparingly diffused aud endemic genera, the same want of any recognizable
relations between extent of geographical distribution, number of species, and the ir variation, prevails,
reuderiug vain any attempt to characterize them by snch general terms as shall convey a more accurate
or definite idea, than, th a t iu whatever light we regai’d them they are all very variable ; the
absolutely local and well-marked genera, as Alseuosmia, Hoheria, and Carmichælia, being quite as
much as or more so than the others. This leads to the last remai’k.
[d,) ^Yi'e the New Zealand plants more variable than those of o ther countries ? This it is almost
impossible to answer, except by giving the general impressions (and such are but too often fallacious)
received during my examinations; and may, I conceive, be better put thus—Have I had comparatively
more difficulty in working out New Zealand plants than those of other countries to whose
floras I have paid equal attention ? I here again find almost insuperable obstacles to a direct answer.
I f I have met with fewer difficulties in other floras, as in those of Tasmania, Europe, and the
Antarctic regions, it may be because my materials were better, aud more assistance was available
from my predecessors, and not because the species were less variable ; again, if I have met with un usual
difficulties in the New Zealand Flora, it is certainly in a great measure to be accounted for by
the very great natural obstacles in the way of a right understanding of the Natural Orders, genera,
and species, some of which I have mentioned at p. xxrii. Upon the whole, I do think th a t the
New Zealand genera are in proportion to the ir numbers more variable than those of other countries
whose botany I have investigated, whether insular or continental ; but I do not wish to express this
opinion so decidedly as to wan’ant any conclusion being drawn from it.
I n the British Flora I find fully seventy widely distributed genera (out of about 513) containing
species as variable proportionally as any in New Zealand, besides many others containing but one or
two very sportive species.
In Tasmania and AustraUa some of the largest genera (as Eucalyptus) are the most protean in
every point of view, the older individuals of each species not only differing widely from the younger,
but also from each other in stature, habit, and botanical characters. In Acacia, on the other hand,
while the young states of m any individual species differ from the old as much as in Eucalyptus, the
latter arc easily limited by constant characters in most important organs. In a third immense
endemic Australian genus, Banksia, the species are very local, and constant as to form ; whilst iii a
fourth equally large and almost equally local genus of the same order, Persoonia, the species vai-j'
* Except, indeed, we admit with many excellent botanists, and perluip.s with all our best ones, that the majority
of the European species are reducible to a very few.
INTRODUCTORY ESSAY. ^^XiX
much. Enough has been adduced to show tha t this sulijcct is most difficult and obscui’e, and I may
add th a t it is one in which hasty generalization from first impressions has given rise to much error.
2. Genera whose species alter in form or habit. These are—Hymenanthera, Pittosporum, Piagi-
anthus, Melicope, Discaria, Edwardsia, Carmichælia, Ackama, Panax, Aralia, Carpodetus, Coprosma,
Parsonsia, Oka, Weinmannia, Dammara, Thuja, Podocarpus, Dacrydium, Phyllocladus, Rhvpogonum.
Many of the above vary so remarkably th a t botanists have been greatly puzzled by tlic abnormal
forms they present ; thus a state of Hymenanthera crassifolia has been referred to Goodenia, one
species of Weinmannia has been made into two genera, and an Oka has been converted into a
Metrosideros. Some states of Plagianthus urticinus and of Carpodetus serratus (plants of two very
different Natural Orders) are almost undistinguishable, and so are Hymenanthera crassifolia and
Pittosporum obcordatum; so also Mclicijtus micranthus, Panax anomala, and Melicope .simplex,
are often so extremely like one another in foliage as to be confounded when in a dry state. M ith
regard to Carmichælia, Ackama, Weinmannia, most of the Araliaceæ, Coprosma, Parsonsia, and
some of the Pines, the variation is greatest in amount between old and young plants ; hut with
Discaria, Hymenanthera, Pittosporum, some species of Coprosma, Oka, and many Pines, there seems
to be no law, abnormally formed organs appearing on the same branches with normal ones.
From the ahove list it would appear th a t variability of this nature is most frequent amongst
more or less endemic genera and species, but whether in this respect the New Zealand Flora is more
variable than others I have not proved. The Yew, Cedar, Holly, Ivy, and especially Furze and
Juniper, perhaps vary in Europe as much as, or more than, the above ; b u t it is difficult to appreciate
the amount of variability in a familiar object. On the whole I am inclined to th in k th a t the
New Zealand Flora is remarkable for the number of p lants which vary tlius, b u t th a t this peculiarity
is rendered conspicuous by the prevalence of Coniferæ and Araliaceæ, which are variable in all parts
of the world.