434 
May 16, 1895. 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
large masses on the roughest rocks; the Dragon Tree, supposed to be 
one of the oldest and most famous trees in the whole world, specimens 
of which are now growing at Kew ; the Canary Palm, Filix canariensis ; 
and the Tree Heath, Erica arborea. 
Pinus canariensis, which is indigenous to the island, is a handsome 
tree, and the wood is largely used in the construction of balconies. Views 
were given of botanic and other gardens in the Canaries, which were 
very beautiful, each having a decidedly tropical appearance. Dr. Morris 
showed specimens of several flowering plants which are natives of these 
regions, such as Ranunculus cortusifolius, one of the prettiest of the 
species, growing well in mountainous districts. Wallflowers are found 
at a high elevation, and Cineraria cruenta, a fine flowering plant, is 
seen in great numbers. 
Statices of several varieties hail from these climes, as also does the 
Marguerite, which is so largely grown for window decoration, together 
with Cytisus racemosas and filipes, both of which are well known in 
English gardens. About 100 plants, natives of the Canary Islands, are 
now growing at Kew. A picture and description was given of the 
Royal Palm of Cuba, or the Travellers’ Joy, as it is more often called 
from the fact that it accumulates and stores water, which by wayfarers 
is much appreciated. A massive Fig tree was also depicted which 
produced large fruits in great numbers, but which unfortunately were 
unfit for food. The lecturer gave a graphic description of journeys 
through the islands, and mentioned many plants that make their home 
there, amongst others being Myrtles, Bougainvilleas, Orange and Lemon 
trees. Euphorbias, Aloes, Cacti, Eucalyptus, and Araucaria excelsior. 
He dealt at some length on the climatic influences, soil, and conditions 
under which many of the native plants grow, and in conclusion of his 
most interesting lecture was accorded a hearty vote of thanks. 
THE PHYSIOLOGY OF PLANTS. 
We have recently received a very useful book—namely, “A Popular 
Treatise of the Physiology of Plants,” written by Dr. Paul Sorauer, 
Director of the Experimental Station at the Royal Pomological Institute 
in Proskau (Silesia). The work has been translated by F. E. Weiss, 
B.Sc., F.L.S., Professor of Botany at the Owens College, Manchester, 
and is published by Longmans, Green, & Co., London. The book is 
lucidly written in plain language, easily understood, and the teaching 
imparted is well depicted in thirty-three illustrations. The author has 
grasped the whole subject in an exhaustive and comprehensive manner, 
giving a thoroughly scientific account of the functions of the various 
organs of plant life, and at the same dealing with practical applications 
of the principles of vegetable physiology. 
Professor Sorauer, in addition to being an authority on the diseases 
of plants, was for many years the director of an institution which had 
in view the scientific training of gardeners and agriculturists. It might 
have been in this capacity that he became aware of the existence of a 
long-felt want, which his book supplies—viz., imparting scientific 
knowledge in language easily understood and comprehended by the 
ordinary class of gardeners, and his book is worthy a place in every 
gardener’s library. The author has carefully avoided any mixing of 
subjects, thoroughly dealing with one before proceeding to the next. 
He commences by showing what conception a gardener should form 
of a vegetable organism, and what the functions are of the various 
organs of a plant, and in dealing with the structure of the root takes in 
rotation the absorptive portion, the root tip, the conducting portion, and 
the process of conduction. The nutrition of the root is thoroughly dealt 
with, showing what substances must be present in the soil for the 
continuous nutrition of plants ; the effect of the nutritive substances 
on the plant, and the form in which they enter it ; also the way the 
root finds the nutritive substances in the soil. It is shown how soil 
can be improved so as to obtain the best crops, how the nutrition 
of pot plants may be effected, and the way in which roots obtain their 
necessary supply of air; moreover, the author shows how roots should 
be treated in transplanting, pruning, and in repotting. 
The stem is next taken, showing the structure of the same, and how 
its functions are performed. After which comes the leaf, explaining 
which cells are the most essential, how the leaf is developed, and the 
important mission it has to fulfil. The author goes on to show why the 
growths of cultivated plants must be pruned, what is the least injurious 
form of a cut, and how summer pruning differs in its results from tW 
of the winter. Also the effect of the different methods of pruning, and 
bow it must be conducted to regulate the development of the tree. 
Propagating is an interesting subject, showing what is meant by, 
end the use of layering ; the rules that should be followed in rooting 
cattiugs ; the objects in view during the process of budding and grafting, 
and how the operation should be performed, and to what extent scion 
and stock influence each other. 
The theory of watering shows why special attention should be paid 
to this operation, after which follows an exhaustive chapter on the 
flower, showing of what parts it consists, how single and double 
blooms are developed, and how a gardener can determine such develop¬ 
ment. The formation of fruits and seeds are also explained, and the 
•conditions governing their production elucidated. In short the book 
is extremely interesting and very instructive. The following extract 
will indicate its character ;— 
How Should Roots be Treated ik Transplanting 1 
“ In the treatment of the roots of our cultivated plants we must first 
consider what part the root plays in the economy of the plant; and 
secondly, whether it is of economic value for us. In the case of annuals, 
it is the rapidly growing absorptive and fixing organ ; in perennials, 
besides absorbing the water contained in the soil, it serves also partially 
as a storehouse for reserve material, which the plant wishes to keep for 
the next vegetative period. In fleshy or tuberous roots, the storage 
function lasts for the greater portion of the life of the plant. 
“Its chief function is as an organ of absorption for the nutritive 
solutions of the soil. It is self-evident that, other things being equal, 
the development of the upper portions of the plant, especially of the 
assimilating leaves, will depend upon the amount of nutritive sub¬ 
stances which are absorbed. Conversely, the greater development 
of the leaves will result in a greater production of organic matter 
(assimilated substance), and, therefore, more of this plastic matter will 
reach the root system, and supply it with the means for producing new 
ramifications. 
“ The above - mentioned reciprocity must always be taken into 
account. If sickly plants with few leaves, or no leaves at all, are able 
to form new roots, and if, on the other hand, plants with feeble or 
damaged roots are able to produce new leaves, it is obvious that such a 
growth must take place at the expense of reserve material which is 
stored up in the main axis of the plant. 
“ In the treatment of plants which are restoring their root system by 
the production of accessory roots, the first rule is to so reduce the work of 
the leaves that it is in harmony with the activity of the roots. 
“ This rule is not confined to pot plants, but applies equally to plants 
grown in the open. The former may be placed during the period of root 
development in close damp houses or frames, so that the amount of their 
transpiration is reduced, and, therefore, corresponds with the reduced 
absorption of the root system. 
” In trees and bushes which are transplanted the root system is 
always injured ; the most apparent injury is the absence of the root tips 
and of the absorptive region immediately behind them. In the case of 
such a reduction of the absorptive root tips, it is evident that the plant 
would possess too large an amount of foliage if all the branches which 
had been formed were left intact. How can the root system, which has 
been damaged and cut in taking it out of the soil, absorb suflScient water 
I for the full development of all its leaves? However much we may 
water the root, it will be of little avail; it may even be injurious to the 
plant, as the saturation of the soil with water may cause decay to set in 
at the cut ends. We must emphatically contradict the view which is 
still held and acted upon by some, that in transplanting trees and bushes 
the branches should be left unpruned. 
“ Transplanted woody plants must have their crowns reduced. It is 
only a question as to how the pruning should take place, so as to assist 
as much as possible the speedy formation of new roots. If we assume 
the roots to be properly pruned, the production of adventitious roots 
depends upon the excess of food substance formed in the leaves over 
1 their consumption. This excess will find i‘s way down the stem into 
I the root system. Again, other things being equal, the amount of 
assimilated food matter available for the roots will depend upon the 
rapidity of development of, and upon the amount of work done by, the 
foliage. The more rapidly, therefore, we can produce a large number of 
actively functioning leaves, the sooner will the stem be in a position to 
pass down material for the formation of new roots. 
“ But with regard to a rapid and strong development of leaf surface 
the several buds of a branch behave very differently, and we may take 
it as a rule that the uppermost buds of every branch are the first to 
develop and produce the largest amount of leaf surface. We must, 
therefore, leave intact some branches, reducing the intervening branches 
to one-half or one-third of their length, according to the amount of 
damage of the root system. In this way we secure the development of 
a number of leaves at the ordinary time, and consequently a certain 
amount of new assimilated food substance. For these few branches the 
amount of sap absorbed is quite sufficient, and the development of 
adventitious roots begins near the cut ends of the rootlets before the 
buds of the pruned branches, which only form a small amount of leaf 
surface, have begun to open. The absorptive organs will, therefore, have 
increased in proportion to the new leaf surface. The method of ‘ partial 
pruning ’ deserves the preference for transplanted trees and bushes.” 
ARGON IN PLANTS. 
I AM indebted to Mr. G. Abbey for the trouble he has taken 
(page 412) in replying to my query on page 388, re the above subject. 
In the original article on “ Plant-forming Elements,” we were informed 
that ‘‘argon enters into the composition of plants ; ” the fact stated by 
Mr. G. Abbey—namely, that argon is present in plants, can only be 
proved by experiments similar to those carried out by Professor Ramsey, 
and as he failed to obtain it, we must either suppose that Mr. Abbey 
has been more successful than the learned professor, or it is merely an 
assumption on his part. 
The information given in the first part of Mr. Abbey’s reply is 
simply a repetition of the statement made by the discoverers before the 
Royal Society. His statement respecting the discovery of hydrogen and 
the composition of water by Cavendish, Scheel’s observation that a 
mixture of hydrogen and oxygen will explode, and also the very remark¬ 
able statement that ” ozone ... is due to the union of oxygen with 
phosphorus ” are interesting, but I fail to see that this is an answer to 
my question. Anyone with the most elementary knowledge of chemistry 
would not expect to find ozone in the vicinity of manure heaps, and are 
' perfectly familiar with the properties of nitrogen. This is, however. 
