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XVlll FLORA OF NEW ZEALAND.
mate of the number of species knoum to botanists is a greatly exaggerated one*, and the prevalent
ideas regarding tlieir distribution no less contracted.
Many more plants are common to most countries than is supposed ; I have found 60 New Zealand
flowering plants and 9 Ferns to be Eiu’opean ones, besides inhabiting vaiious intermediate
countries ; and amongst the lower Orders w’e find a greatly increased proportion of species common
to all countries : thus of Mosses alone 50 are found in New Zealand and E u ro p e t ; of Hepaticæ 13 ;
of Algæ 45 are also natives of European seas; of Eiuigi nearly 60; and of Lichens 100.
So long ago as 1814 !Mr. BrownJ drew attention to the importance of such considerations, and
gave a list of 150 Eiu-opean plants common to Australia. The identity of many of these has repeatedly
been called in question, but almost invaiiably eiToneously, added to which more modern
collectors have gi’eatly increased the list.
The too prevalent idea th a t the plants of newly discovered, isolated, or little visited localities
must necessarily be new, has been a fertile source of the undue multiplicatiou of species. There are
very many cases of natiu’alists having been so impressed with this idea, th a t they have not thought it
worth while to consult either books or herbaria before describing the plants from such spots. The
New Zealand Flora presents several instances of this ; two conspicuous ones occur in the genus
Ooeàlls ; one, O. corniculata, is amongst the most widely diffused and variable plants in the world ; of
its varieties no less than seven or eight species have been made, most of them supposed to be peculiar
to New Zealand; not only is 0 . corniculata hence excluded from the flora, but in the descriptions of
these its varieties, no allusion is made to th a t plant§. In the case of the other species the error is
more excusable, and maybe stiU open to questionjl ; it is th a t of O. Magellanica, originally discovered
in Fuegia, and imperfectly described by Forster, whose very indifferent specimens of it are in the
* According to tlie loose estimate of compilers, 100,000 is the commonly received munber of known plants :
from a multiplicity of data I can come to no other conclusion but that half that number is much nearer the truth.
This may well be conceived, when it is notorious that nineteen species have been made of the common Potato, and
many more of Solanum nigrum alone. Pteris aquilina has given rise to numerous book species, Vernonia cinerea of
India to fifteen at least. Many of the commonest European plants have several names in Europe, others in India,
and still others in America, besides a host of garden names for themselves, their hybrids and varieties, all of which
are catalogued as species in the ordinary works of reference whence such estimates are compiled.
t In fact the distribution of some Cryptogams is so wide, that I have visited a spot in a high southern latitude,
nearly all whose plants are not only identical with those of Great Britain, but inhabit many intermediate temperate
and tropical countries. Cockburn Island, in lat. 64° 12' S. and long. 64° 49' W., nearly fulfils this condition
; I thereon collected nineteen plants, of which thi-ee-fourths are natives of England.
X Appendix to Flinders’s Voyage, vol. ii. p. 592.
§ I have stated very confidently in the body of this work that eight of Cunningham’s and Richard’s species of
this genus are all referable to one. This view will probably not meet the approbation of the local botanists, who will
point to the constancy with which some of the states retain their characters under varied conditions. I value such
facts very highly, and attach great weight to them, and did these varieties occur only in New Zealand 1 should
perhaps have withheld so strong an opinion on the subject; but such is not the case. 0. corniculata varies as much
in numerous other parts of the world ; and admitting, as every one must, that varieties are known to retain their
characters with more or less constancy for certain periods, some otber evidence is necessary to shake the opinion of
the botanist who grounds his views on an examination of the plant from all quarters of the globe.
II As no identification is proved till all the organs of the plants to be compared have been studied, there is yet
a possibility of these three species proving distinct, but I do not at all expect it; the only diflerence I can find is
a greater obliquity and emargination of the petals of the New Zealand species, but that character varies so much
both in this plant and in others of the genus that it loses all specific value.
British Museum. When rc-found in New Zealand it was described as new, and called 0 . cataractes,
and when found a th ird time in Tasmania, was called by still a th ird name, 0 . lactea. In this case
a more important fact was smothered than th a t of tlie distribution of O. corniculata, namely, th a t of
a very pecidiar plant of the south temperate zone being common to these three widely sundered
localities.
Many similar instances might be added, for there are several New Zealand plants (as Pteris
aquilina) th a t have a different name in almost every country in the world, and, partly from
changes in nomenclature, partly from the reduction of species, I have found myself obliged to quote
1500 names for the 730 New Zealand flowerbig-plauts described, and I believe I might have doubled
the number had my limits not obliged me to reduce the synonymy as much as possible ; in many
cases too much, I fear, for the requirements of working botanists in Europe.
§ 4.
The distribution o f species has been effected by natural causes, but these are not necessarily the
same as those to which they are now exposed.
Of aU the branches of Botany there is none whose elucidation demands so much preparatory study,
or so extensive an acquaintance with plants and their affinities, as th a t of the ir geographical distribution.
Nothing is easier than to explain away all obscure phenomena of dispersion by several speculations
on the origin of species, so plausible th a t the superficial naturalist may accept any of them ;
and to te st their soundness demands a comprehensive knowledge of facts, which moreover ru n great
risk of distortion in the hands of those who do not know the value of the evidence they afford. I
have endeavoured to enumerate the principal facts th a t appear to militate against th e probability of
the same species haring originated in more places (or centres) than one ; b u t in so doing I have only
partially met the strongest argument of all in favour of a plurality of centres, viz. the difficulty of
otherwise accounting for the presence in two widely sundered localities of rare local species, whose
seeds caimot have been transported from one to the other by n atural causes now in operation. To take
an instance : how does it happen th a t Edwardsia grandiflora inhabits both New Zealand and South
America ? or Oxalis Magellanica both these localities and Tasmania? The idea of transportation by
aerial or oceanic currents cannot be entertained, as tbe seeds of neither could stand exposure to the
salt water, and they are too heavy to be borne in the air. Were these the only plants common to
these widely-sundered localities, the possibility of some exceptional mode of transport might be admitted
by those disiucbued to receive the doctrine of double centres; but the elucidation of the New
Zealand Flora has brought up many similar instances equally difficult to account for, and has developed
innumerable collateral plieiiomena of equal importance, thougb not of so erident appreciation.
These, wliich all bear upon the same point, may be arranged as follows :—
1. Seventy-seven plants ai’e common to the three great south temperate masses of land, Tasmania,
New Zealand, and South America.
2. Comparatively few of these are universally distributed species, the gTeater part being peculiar
to the south temperate zone.
3. There arc upwards of 100 genera, subgcnera, or other well-marked groups of plants entirely
or nearly confined to New Zealand, Australia, and cxtra-tropical South America. These are represented
by one or more species in two or more of these countries, and they thus effect a botanical relationship
or affinity between tlicm all, which every botanist appreciates.
d 2