I
;.i
i |i|
I ';i>i!
\ i
■I I
many liunclred specimens of the plant, gathered in all parts of the south temperate hemisphere, and
have found, after a most laborious comparison, th a t I could not define its characters with sufficient
comprehensiveness from a study of its New Zealand phases alone, nor understand the la tte r without
examining those of Australia, South Africa, and South America. The resident may find two varieties
of this and of many other plants, retaining their distinctive characters within his own range of observation
(for th a t varieties often do so, and for a very uncertain period, both wlien wild and also in
gardens, is notorious), and he may perhaps have to travel far beyond liis own island to find the link
I have found, in the chain of forms th a t unites the most dissimilar states of Lomaría procera; but he
can no more argue thence for th e specific diflerence of these, than he can for a specific difference between
the aboriginal of New Zealand and himself, because he may not find intermediate forms of his
race on the spot. We do not know why varieties should in many cases thus retain their indi^d-
duality over gi’eat ai'eas, and lose them in othe rs; but the fact th a t tliey do so proves th a t no deductions
drawn from local observations on widely distributed plants can be considered conclusive. To
the amateur these questions ai’e perhaps of very trifling importance, but they are of great moment to
the natui’alist who regards accurately-defined floras as the means for investigating the great phenomena
of vegetation j he has to seek tru th amid errors of observation and judgment, and the resulting
chaos of synonymy which has been accumulated by thoughtless aspirants to the questionable honour
of being the first to name a species*.
There are many causes which render it extremely difficult to determine the limits of species, and
in some genera the obstacles appear to increase, the more the materials for studying them multiply,
and the more we follow our analysis of them into d e ta il; hence the botanist is often led on to an
indefinite multiplication of species (-with increased difficulty of determining those already established),
or to a reduction of all to a few, or to one variable species. My omti impression is, th a t tlie progress
of botany points to the conclusion th a t in many genera we must ultimately adopt much larger views
of the variation of species than heretofore, and tha t the number of supposed kinds of plants is (as I
shall indicate elsewhere) greatly over-estimated; if it be not so, we must either admit th a t species are
not definable, or th a t there are hidden characters throughout aU classes of the vegetable kingdom, of
which the botanist has no cognizance, and towards the acquirement of which, if they are ever to be
revealed, all efforts in the direction in which we have been advancing appear to be vain. Could systematists
as a body be accused of carrying out their investigations in an unphilosophical manner or
spirit, or without due attention to aU the modes of testing the validity of characters, afforded by the
study of living aud dried plants, by direct observation, and by experiment, there might be hopes of
such a revelation; h n t such hopes are inconsistent with the great advances tha t have been made in
systematic botany, which, having all tended to a more perfect knowledge of the affinities of plants, we
are assured have been the effect of progress in the right direction.
Of the genera to which I here allude as variable, there are many in New Zcalandf; some of
* The time however is happily past when it was considered an honour to be the naraer of a plant; the botanist
who has the true interests of science at heart, not only feels that tlie thrusting of an uncalled-for synonym into
the nomenclature of science is an exposure of his own ignorance and deserves censure, but that a rider range
of knowledge and a greater depth of study are required, to prove those dissimilar forms to he identical, wliich any
superficial observer can separate by words and a name.
■f M. Bory de St. Vincent has observed (Voyagg dans les Quatre principales lies des Mers d’Afrique) with
reference to insular floras, that their species are generally variable, an hypothesis scarcely compatible with the fact
that the proportion of species to genera in islands is always small, because the proportion of imported plants, which
is considerable in an island, is made up of species of different genera, having no affinity with one another, and
there are mundane, th a t is, found in all or most temperate or tropical eHmates, as Ranunculus, Clematis,
Senecio, and many Grasses and F e rn s ; and we cannot yet tell w hether the difficulties are greater
with them than with the more local or endemic genera, as Coprosma, Celmma, Alsmosmia, and Dia-
cophylUm. Of the mundane genera again, some are chiefly composed of species which ai^ local (as
is the ease with the three first mentioned), whüe of others the species tliemselves are widely distribiited,
as those of iewM«, and many Ferns. ^ ^
The fact of a plant having a wdde range implies its being exposed to climatic differences th a
often induce change, and the consequent propagation of forms or races th a t cannot be recognized as
members of one species, without full series of specimens fi-om many localities. I f we allow a sufficient
time, it is quite reasonable to suppose th a t geological or other natural causes (produciug a
change of climate) may isolate by sea or desert, or by the intrusion of stronger plants th a t monopolize
the SOÜ, the outlying abnormal states of a species th a t was once uniformly spread over an area.
To connect those dissevered members is often a work of great difficulty, for individuals of such races
frequently retain their character even when they have been under cultivation for many years.
Hybridization has been supposed by m any to be an important clement in confusing and maskmg
speeies*. Nature, however, seems effectually to have guarded against its extensive operation and its
effects in a natural state, and as a general rule the genera most easily hybridized in gardens, are not
those in which the species present the greatest difficulties. W ith regard to the facUity with which
hybrids are produced, the prevalent ideas on th e subject are extremely erroneous. Gärtner, the
most recent and careful experimenter, who appears to have pursued his inquiries in a tru ly pliiloso-
phioal spirit, says th a t 10,000 experiments upon 700 species produced only 250 tru e hybridsf. I t
would have been most interesting had he added how many of these produced seeds, and how many of
the latter were fertile, and for how many generations they were jiropagated. The most satisfactory
liroof we can adduce, of hybridization being powerless as an agent in producing species (however
much it may combine tliem), are the facts th a t no hybrid has ever afforded a character foreign to th a t
of its parents, and th a t hybrids are generally constitutionally weak, and almost invariably barren.
Unisexual i trees must offer many facilities for the natural production of hybrids, which, nevertheless,
liave never been proved to occur, nor are such trees more variable than hermaphrodite ones.
notliing ill common but tlieiv facility for transportation. From the above-mentioned hypothesis it would hence result
that whilst the differences of one degree (specific) are small and inconstant, those of a higher degree (generic) ore
great and trenchant. To a certain c.xtent, however, these facts are not incompatible, for we can imagine a flora
wholly composed of a few genera as well marked (generically) as Cofromia and Alseitosmia, whose species may yet
be as undcfinable; or again, species may be well marked, yet variable in characters which would in no one’s opinion
be of specific value.
* Hybridization as an agent in confusing species is a very favourite argument with those who are fond of
founding species on inconstant characters; when shown a specimen combining two such spurious species, they at
once pronounce it a hybrid—a very simple way of getting rid of a difficulty. In Ferns, the most variable of all
plants, hybrids were once generally admitted to exist, but the observations of Suminski have led to the discovery
of their sexual organs, whose arrangement and structure seem to preclude the possibility of such a phenomenon.
f See his observations on muling, Ilort. Soc. Journ. vol. v. and vi. 1850-1851.
X Unisexual plants are very interesting in many points of view, and in none more than in the varying development
of the sexes according to circumstances. Observations on this subject are veiy much wanted : it has
been stated to depend on local circumstances whether the seeds of a bisexual plant shall come up male or female;
and the fact of both kinds of flowers, or even of hermaphrodite flowers, often occurring on a plant that usually perfects
one sex only (as in the moucecious Hop-plant described by Mr. Masters in Gard. Chroii. 184-7), shows tliat
we may even speculate on the possibility of dimcious plants having sprung originally from a single parent, whose off