December 8,1894. 
THE GARDENING WORLD. 
237 
with even greater force to plants grown in small 
quantities of soil in pots. Aquatic plants proper 
have made provision for a supply of air ready to 
hand even when immersed in water or when their 
roots are buried in mud. The average gardener 
recognises that fact, even if unable to explain it. 
When the soil becomes sodden, and almost the 
whole of the air expelled from the interstices of the 
same, he says it is sour, and that is sufficient science 
to urge him to initiate and effect a remedy. 
The stem of an Apple consists of a small quantity 
of pith in the centre, a relatively large quantity of 
wood around this, then an extremely thin ring or 
layer of cambium, and outside of all comes the 
protective layer of bark. The pith and wood are 
practically dead matter, so that after the fall of the 
leaf, the thin layer of cambium, the buds and the 
inner bark constitute all the real living parts of the 
tree. The branches and twigs are all modelled upon 
the same plan, only on a smaller scale. Though 
dead, these parts are not functionless; for do they 
not serve to support the head of the tree and in 
summer to distribute the leaves over a given space, 
so that every one will be properly exposed to sun¬ 
light and air ; and later on to bear the fruit necessary 
for the preservation of the species ? The trunk and 
branches serve as arteries or channels for the convey¬ 
ance of water containing plant food to the leaves ; 
and in winter the younger parts at least serve as 
stores for warehousing reserve materials to assist 
the early growth of the following spring and summer. 
Nor, although dead, must we consider the wood as 
in a state of decay or rottenness. An Apple tree 
may stand from ioo to 200 years under favourable 
conditions, and the Pear for 400 years'; but it is 
necessary that the roots be sound and the protective 
bark well preserved to guard against the corroding 
action of air, rain and frost as well as against the 
ravages of insects and fungi. We are told of other 
trees such as the Yew and Sequoia which live per¬ 
haps 1,000 years and resist decay. Hence we must 
guard against injury to the bark of trees under our 
care, and avoid the use of the saw upon large 
branches where possible, or on the other hand to 
protect the exposed wood against the action of 
atmospheric influences. The removal of large limbs 
in any case is prejudicial to longevity. The fact 
that the cambium layer and its accessory parts 
constitute the only really live part of the tree, 
explains their importance in the processes of budding, 
grafting and inarching. 
The leaves of an Apple tree are all important to 
ts welfare, in fact absolutely essential to its continued 
existence. About half the dried weight of it consists 
of carbon, and this the leaves absorb from the 
atmosphere in the form of carbon dioxide. Experi¬ 
mental science has proved, in some cases at least, 
that this is more extensively effected by the upper 
than the under surface of the leaves notwithstanding 
the popular belief to the contrary, that it is accom¬ 
plished through the medium of the stomata or pores, 
usually most abundant on the lower side of the 
same. The leaves of the tree constitute so many 
laboratories in which the decomposition of carbon 
dioxide takes place and the simple ingredients of 
plant food are built up into complex ones to be 
distributed over the tree presently for the purpose 
of fresh growth, the reparation of injuries or for 
temporary storage somewhere or other. The 
chlorophyll or leaf green is the active agent, under 
the influence of light, heat and air by which these 
processes are effected ; and furthermore, it is the 
only agent by which organic matter is originally 
built up on our globe, whether for the sustenance of 
plants or animals. The carbon dioxide above men¬ 
tioned is absorbed and passed into the interior of the 
leaves iff a state of solution, through the medium of 
the water or moisture permeating the outer or super¬ 
ficial cell walls. This may be regarded as an act of 
feeding and the carbon taken in is the only element 
of plant food of importance that is taken from the 
atmosphere. 
The leaves perform still another function of im¬ 
portance, and that is the process of respiration. 
Oxygen is as necessary to a tree as to an animal for 
the purpose of keeping the vital parts alive and to 
give the necessary energy for continued work and 
growth. Almost the whole of the oxygen absorbed 
in combination with carbon is liberated again as 
pure oxygen, and during the day the quantity of 
that gas obtained from different sources is sufficient 
to mask or hide the real process of respiration which 
proceeds day and night; but as the absorptive 
activity and the building-up of new materials cease 
during the night then it may be ascertained that 
leaves draw largely upon the atmosphere, for the 
oxygen that is absolutely essential to life. This 
free oxygen never goes to the building-up process 
but is solely concerned in destroying a part of that 
which has already been built up, and that too for 
the good of the rest. This then is the process of 
respiration, and as a result of it carbon dioxide, 
popularly termed carbonic acid gas, is given off into 
the atmosphere as in the case of animals. 
During the day another process, which we cannot 
afford to ignore, is effected by the leaves—namely 
transpiration. That, like the carbon dioxide of 
respiration, maybe regarded as a waste or excretory 
process of superfluous matter. By far the larger 
quantity of water taken in by the roots is unnecessary 
for taking part in the construction of the tree, con¬ 
sequently it has to be liberated again, and this is 
done by the leaves, through the medium of the pores, 
whose function is to promote this process. This 
goes on actively during the day when the temperature 
is sufficiently high as in summer, but at night it 
entirely ceases. The whole plant then gets gorged 
with water, which filters into the cavity of the vessels, 
and finds an exit through the water pores at the 
tips of the veins of the leaves, but presumably more 
actively during the younger stages of the same. The 
transpiration of the leaves explains why a vine is so 
much less liable to bleed after the foliage is fairly- 
well developed. The effect of root pressure is to 
gorge the rods with water, but the pressure of water 
or sap finds relief when the leaves liberate the super¬ 
fluous portion which they pass into the atmosphere. 
Flowers and Fruit. 
The ultimate object of a plant is to reproduce its 
kind, and this it does by the formation of flowers 
and the development of fruit. The flowers of an 
Apple tree, or rather the floral envelopes, are first 
protective and then showy in the case of the petals. 
Not only are the flowers handsome, but they are 
also fragrant in certain cases at least, and when one 
looks upon them with the eye of a naturalist one can 
hardly fail to conceive that their beauty is intended 
to attract insects and so ensure fertilisation. The 
production of fruit is primarily intended for the 
benefit of the species, and afterwards for the use of 
man or other animals. If asked to explain how I 
arrive at my conclusions, I argue from the fact that 
the large and fleshy or juicy Apple was intended to 
be eaten, no matter by what animal; while the 
harder and less palatable seeds of the ripe fruit 
would be discarded and dropped about, thus dis¬ 
seminating the species broadcast. The improve¬ 
ment of the original wild crab was probably owing 
as much to man as the inferior animals, for to go no 
farther back than the stone period the remains of 
the Swiss lake dwellings prove that the Crabs grow¬ 
ing wild in the woods in those days were collected 
and stored to be utilised as food by the human 
inhabitants. There are sweet as well as sour crabs, 
and the difference was doubtless detected in those 
times, and the best ones most frequently eaten and 
the seeds scattered about, so that in course of time 
the sweet varieties would be more prevalent than 
the sour ones, even though not cultivated, but 
common property. 
Artificial Reproduction. 
It may be argued that modern and improved varieties 
of Apples need not produce seeds seeing that they 
may be increased by means of budding, and grafting, 
and by cuttings. The fact must not be overlooked 
that all the varieties we now possess have been 
obtained at one time or another as chance seedlings, 
or purposely by the selection and sowing of seeds 
from particular kinds, or by the actual crossing of 
varieties, or the hybridisation of species, whatever 
that may mean, to obtain improvements upon the 
parents. Once the desirable varieties have been 
obtained we can propagate them in the above men¬ 
tioned ways ; but the question remains to be deter¬ 
mined whether individuals could be perpetuated 
indefinitely by such means. Now and again a ques¬ 
tion of deterioration of old kinds crops up, but we 
are scarcely in a position (for want of data) to 
determine whether the constitution of the tree or 
the quality of the fruit is subject to deterioration 
through old age of the individual, because if we go 
back to a period equivalent to the natural life of a 
tree we greatly reduce the number of kinds now 
actually in cultivation, and to double that period we 
arrive at a time when few if any existing kinds had 
originated. Many thousands must have been dis¬ 
carded during the last thousand years to make way 
for the varieties we now cultivate. 
[To be continued.) 
Hardening Miscellany. 
POLYANTHUS FROM THE MIDLANDS. 
We received a bunch of Polyanthus the other day 
from Mr. G. Harvey, The Gardens, Stanton Hall, 
Bakewell, which is situated in the north of Derby¬ 
shire. Our correspondent is also able to gather 
Carnations and Roses from the open garden, so that 
the weather is evidently mild and favourable to the 
growth of vegetation in the Midlands as it has been 
in the southern and western counties, The flowers 
of Polyanthus come with the breath of spring, for 
their fragrance forcibly reminds us of sunnier times 
and the promise of summer with all its potentialites 
of fresh harvests of flowers, fruit and vegetables. 
They presented a considerable range of colours in 
red, crimson, crimson spotted with white, pale and 
dark yellow and white with a yellow or orange eye. 
It is usual for the stalks of flowers such as Butter¬ 
cups and Daisies to be very short when they develop 
during relatively cold but open weather. Those of 
the Polyanthus sent us were 3 in. or 4 in. to the base 
of the truss of flowers, but to the top of the latter 5 
in. and 6 in. Possibly the lower portions of the 
stalks were not sent us. Nevertheless the facts 
presented speak of relatively highly favourable condi¬ 
tions to plant life at the end of November. 
ASPLENIUM FRAGRANS FOENICULACEUM. 
This fern is a native of tropical America, but from 
what we have been able to see and learn it is not in 
cultivation. It belongs to the same group as A. 
Adiantum nigrum, A. furcatum and some others well 
known and widely cultivated. The pinnae and their 
divisions are wedge-shaped, and the divisions are 
also characterised by the same mode of arrangement, 
and vary in the depth of cutting and in width. The 
Kew specimens sent us by Mr. J. Birkenhead, came 
from the herbarium and are doubtlessly correct, but 
they were only seedlings and therefore not in their 
true or adult character, so that little can be gained 
by comparing them with garden specimens under the 
name of A. fragrans foeniculaceum. The fronds and 
plants we have recently examined from various 
sources belong in most cases to A. bulbiferum 
fabianum. As a species, A. bulbiferum is extremely 
variable although the type and A. b. fabianum are 
connected by various intermediate forms, such as A. 
b. laxum, A. b. pumilum, A. b. biforme, and others. 
The type has the broadest segments. A. Colensoiis 
now reduced to A. b. minus. Another specimen sent 
us turned out to be A. viviparum belonging to the 
section Darea, and therefore widely distinct from A. 
fragrans foeniculaceum. The latter, according to 
description, is a finely divided form with linear seg¬ 
ments, but the insertion of the sori is different from 
that of the Ferns above mentioned. 
ERYNGIUM EBURNEUM. 
The stems of this Brazilian species attain a height 
of 6 ft., and form long, cylindrical or club-shaped 
panicles of whitish flowers, by some described as 
ivory-white. The flowering portion is about half 
the length of the stem, and develops numerous 
short, side branches bearing clusters of flower heads. 
The spiny bracts surrounding the heads and so con¬ 
spicuous in European and Asiatic species are here 
absent or so reduced as to have no bearing whatever 
on the ornamental aspect of the plant. The leaves are 
spiny-serrate at the margins, 2 ft. to 3 ft. long, and 
not unlike those of some species of Pandanus. 
Several of the South American species have foliage 
of this type, and are therefore very distinct from 
the better-known and dwarfer species in cultivation. 
A wood-cut illustration of E. eburneum is given in the 
Revue de L'Horticulture Belqe, for December. Unfor¬ 
tunately the species of this type are not quite hardy, 
and require protection in severe winters by covering 
the crowns with ashes or dried leaves to keep the 
roots dry and preserve them from frost. The 
foliage may be protected by tyiDg it in a loose 
bundle and covering with a piece of tarpaulin, with 
branches of broom or a covering made of straw 
during the continuance of severe frost. 
TWO NEW AZALEAS. 
A large number of the Ghent Azaleas obtained by 
crossing A. mollis with A. sinensis is characterised 
by having flowers varying from pale yellow to deep 
salmon or orange, but at last a distinct acquisition 
has been made in a variety named La Czarine or La 
