331 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
[ Apiil 24, 1890. 
suspected ; and now Mr. Campbell has added to the obligations of 
fruit growers by the careful and exhaustive experiments that we 
were aware were being conducted at Glewston Court, and of which 
he is able to say in respect to the use of Paris green that he “ can 
report favourably all round.” The remedy has been frequently 
mentioned in our columns as proving effectual in America, and the 
strength and method of applying the poison have been indicated ; 
but we have not hitherto been able to publish any narration of the 
successful use of Paris green in this country, though it is said to 
have been found fatal to caterpillars and harmless to trees by a 
nurseryman. It will be perceived that caution is advised in the use 
of the arsenical preparation, and the strength of 2 ozs. to 25 gallons 
of water should not be exceeded ; also the importance of keeping 
the water well stirred should be remembered, or the fine crystals 
will sink to the bottom of the vessel. Note should also be taken 
of the extreme minuteness of the early hatched caterpillars, which 
may, and doubtless do, abound on trees when their presence is 
not suspected. A magnifying glass reveals their existence when 
they are not visible to the naked eye. On the part of the fruit 
growers of the kingdom we thank Mr. Campbell for making known 
the result of his endeavours to conquer an enemy that, if unchecked, 
will assuredly render fruit growing impossible in some important 
fruit growing districts in the southern and midland counties.] 
VARIATION IN PLANTS. 
The plant world affords abundant subjects of the deepest 
interest to students of all classes, especially to amateur and pro¬ 
fessional horticulturists, who are concerned, not only with the 
welfare of individual plants, hut with their improvement either 
for ornament or use. An observer finds much to excite wonder in 
a most cursory review of the vegetable kingdom ; the marvellous 
variety of forms, the wealth of floral beauty, the numberless 
valuable food and other products of so much importance to man¬ 
kind, furnish ample material for investigation and thought. No 
section of this great subject having a direct bearing upon the art 
of gardening has, however, received the same scientific attention as 
the fertilisation and hybridisation of plants. Some of the most 
celebrated naturalists, as, for example. Dean Herbert and Charles 
Darwin, have studied it closely, experimented largely, and recorded 
their own with others’ observations in books that rank amongst 
the standard works of the English language. Ever since the 
phenomena connected with hybridisation has been in some degree 
comprehended practical men have not been slow to take advantage 
of the means it afforded to increase the diversity, beauty, and use¬ 
fulness of plants. 
For ornamental purposes alone it was soon ascertained that the 
range of floral colouring in particular favourites could be greatly 
extended by a judicious and systematic crossing and seed-raising. 
Then, too, the same methods applied to edible vegetables and 
fruits, with farther aid of selection, have been found to yield 
important results by extending the seasons at which they could be 
obtained and by diversifying their flavours. Such beneficial re¬ 
sults as these, in addition to the interest attaching to the matter, 
are sufficient to prove that the subject is worthy of close attention 
on the part of all engaged in horticulture, especially as there is still 
abundant scope for experimental research. In the following re¬ 
marks it will not be possible to completely review the whole 
of this extensive subject, but we can discuss it generally ; and in 
pointing out the more important facts we may stimulate others to 
closer observation, and upon the development of this faculty 
depends a good deal of what is termed successful gardening. 
The power of man in the production of plant forms depends 
entirely upon the inherent tendency to variation marking the 
greater portion of the vegetable world. In our meadows, heaths, 
and in any uncultivated district it is easy to find examples of this 
amongst the native plants of this country. The differences are 
often very slight, and such as only an experienced eye could 
detect; but, on the other hand, forms are occasionally found un¬ 
doubtedly having a common origin, yet with strongly marked 
characters that cannot be overlooked. It is only necessary to refer 
to the British Ferns for instances illustrating these observations, 
but many fiowering plants afford examples of scarcely less value. 
Of course variations in one species are here referred to, but what 
we regard as a species is simply a group of individuals agreeing in 
certain characters and possessing some peculiarities of formation by 
which they can be distinguished from all other members of the 
vegetable kingdom. Now, we find amongst animals of one species, 
or even of one variety, sufficient characters to render them easily" 
distinguishable from their near relatives, and by close observation 
it is possible to detect, and even become familiar with, points of 
difference that in the same way mark the individual plants raised 
from one species or one parent. Here we have the commencement 
of a divergence that may be perpetuated and increased, with the 
result that a variety with more or less strongly marked characters 
may be ultimately secured, or forms of even greater value may be 
obtained, for in many races of cultivated plants variations have 
been raised by accident or design that if found in a state of Nature 
would probably have been regarded as distinct species. 
Botanists have frequently had to modify their views respecting 
what constitutes species in some families of plants, as the discovery 
of other forms intermediate between those already known have- 
linked apparently distinct species together so closely that their 
amalgamation became necessary. What may be termed the- 
capacity for variation in particular species cannot be discovered 
at a glance, and it is only wide knowledge of related forms, or- 
experience of the plant’s behaviour under cultivation that permits 
an approach to an accurate opinion to be formed. All do not 
possess the same elasticity, for some species preserve their chiei. 
characteristics unchanged in a wild state, few or no variations are 
found, and they present constant types, often under very diverser 
circumstances, soil, situation and climate. Some of the most 
widely distributed plants are examples of this, and travellers are 
almost startled sometimes by the appearance of a familiar plant,, 
true in all its characters, but thousands of miles from its British 
home. _ 1 u • 
Others, again, are influenced to a certain extent by their sur-^ 
roundings, and we thus have what are termed geographical varieties,. 
all, however, tolerably true to the main type. There are still 
others that vary greatly in one locality, where the differences la 
situation can count for little, and the variation depends upon 
characters being less firmly fixed, and consequently more readily 
influenced by cross-fertilisation. 
Under cultivation we find these various classes of plants behave- 
very differently. Some absolutely refuse to submit to man s inter¬ 
ference or efforts to alter their characters, and retain their dis¬ 
tinctions unchanged. Others after a long course of culture seem 
to have their constitution so disturbed that variation is induced,, 
and when once this is effected it becomes a matter of perseverance, 
in some degree, as to how far it shall be extended, ffhose which 
have been noted as variable in a wild state usually become still 
more so under artificial conditions. They give rise to an astonishing 
diversity of forms, and their fixity of character being once broken 
down they are like plastic moulds in the hands of the experienced 
cultivator, who within a certain range can obtain almost any com¬ 
bination of tints or fioral form he desires. 
In a state of nature we find, therefore, as far as necessarily 
limited observations can determine, that the variability of specks- 
differs greatly, but under cultivation we also see the tendency to 
variability considerably increased. Altered conditions of existence 
are the main causes of this, and it follows if a wild plant by any 
chance should find a home and thrive in a soil and situation greatly 
different from that which its relatives usually occupy, divergence of 
character might be induced and inherited by its descendants. Here- 
we have the first step to a variety, and the differences may become- 
accentuated in succeeding generations, particularly if the character 
so developed affords the plant any help in preserving its existence:- 
by ensuring fertilisation, or by a more vigorous constitution 
enabling it to resist climatic evils. Such variations might and do 
occur without cross fertilisation, simply from the influence exerted 
upon the plant by different conditions of location. When a Chang's- 
is once started it is soon extended, and it is then that cross-fer¬ 
tilisation comes into action with more marked force. 
Amongst many cultivated plants variations are commonly 
obtained from the self-fertilised flowers of one plant without any 
attempt at crossing, but it is true that the results may often 
represent reversion to the characters of former parents, or a com¬ 
bination of these, rather than absolutely fresh productions. 
Examples are afforded by many of the garden annuals and other 
plants usually raised from seed, for it is most difficult to keep any 
selection of these true without large quantities are grown together, 
and even then much “ weeding ” is often required. Under culti¬ 
vation therefore, as in Nature, variability is to some extent caused 
by altered conditions of existence, and subsequently rnany varia¬ 
tions that appear, may be simply reversions or combinations of 
pre-existing characters. 
In gardens another form of variation plays an important part 
namely, “ sporting but it rarely happens that Nature makes any 
provision for the preservation of such freaks, and it is only through 
propagation by cuttings, grafts, and buds that so many have been 
multiplied artificially. It is seldom that they are reproduced 
from seed, though an alteration has been effected that may have 
