668 
June 19, 1886. 
THE GARDENING WORLD. 
tribution of a species by giving rise to individuals 
better adapted to withstand a greater degree of heat 
or cold than the parents, and abler in many ways to 
accomodate themselves to their surroundings and 
changing circumstances. 
Self fertilisation, on the other hand, is a last resource 
to save a species from utter extinction that has from 
some cause or other ceased to be insect-fertilised, either 
through the extinction of the insect, or owing to one 
or other having migrated or shifted its geographical 
distribution independently of the other. Close com¬ 
petition with other more highly attractive flowers might 
limit the number of insects visits, but such might still 
be occasionally cross-fertilised, and it is questionable 
■whether this does not happen to those that are usually 
self-fertilised. The loss of the proper insects, however, 
have doubtless been the cause of much extinction of 
species and forms. In Oplirvs apifera the whole pollen 
masses, owing to their own weight and the slenderness of 
the caudicles fall out of the anther-cells and are easily 
blown against the stigmatic disk while dangling by 
their glands. In several other species of the same tribe 
that are known to be self-fertilised, the pollen masses 
by a degradation of their connecting tissue, fall to 
pieces and drop on the stigma. The same thing happens 
in some of the Neottieae. The filament of the anther 
in some species of Dendrobium is highly elastic and 
contractile, and in D. chrysantlium, serves to scoop out 
the pollinia when the antlier-cap has been disturbed by 
an insect or other means. The pollinia falling on tire 
labellum are caught up by the latter as it regains its 
position and thrown against the stigmatic disk where 
they adhere. This is what happens, provided the insect 
fails to remove them in the proper way. Self fertilisa¬ 
tion also takes place in the same species by the pollinia 
remaining in situ and emitting their pollen-tubes into 
the copious sticky matter produced by the degradation 
of the rostellum, and so passing directly into the 
stigmatic disk. This Recurs regularly and without 
external aid in Chysis aurea. 
Seeds. 
When the pollinia are applied to the stigmatic disk 
the ovules are not even perfectly formed. The column, 
however, commences to grow almost immediately and 
swells to a great size, in some species at least entirely en¬ 
closing the pollen masses and quite losing its original ap¬ 
pearance. The pollinia now undergo their final develop¬ 
mental changes, preparatory to the emission of the 
pollen-tubes that find their way down the column and 
ovary to the microphvle of the ovules in immense 
numbers. The enormous number of ovules or seeds 
after fertilisation is a remarkable feature of the order. 
We have already seen that the pollen leaves its parent 
cell, before having completed its final development, 
and the same thing applies to the seed which is matured 
and desseminated before the embryo has attained any¬ 
thing more than a mere morula-like mass, without 
differentiation into radicle, plumule aud cotyledons as" 
we find in most Phanerogams. This is an obvious mark 
of low organisation, and, however perfectly adapted to 
the surroundings in the primeval condition of the order, 
when our planet presented totally different climatal 
conditions and accompanying circumstances, influencing 
and affecting plant-life. The seeds of Orchids are at 
the present day unable to compete with those of Phan¬ 
erogams, developed along different lines and more 
adapted to accommodate themselves to the existing 
order of things. This applies more especially to British 
Orchids and to temperate countries generally, where 
the native Orchids may be looked upon as a remnant 
of what they have been, and as gradually becoming 
extinct rather than extending their area of distribution. 
There can be little doubt that the weak point of this 
otherwise highly developed order lies in the imperfectly 
developed embryo. The infinitesimally minute and 
light seeds are admirably adapted for distribution by 
the wind and other agencies, and this provision serves 
for their transportation to the often elevated positions 
occupied by epiphytes, but this is all. A single capsule 
of some of our commoner native species would produce 
over 6,000 seeds, while some of the exotic Maxillarias 
have been calculated to contain about a million. This 
number is probably much exceeded by C’attleya gigas, 
and seeing that the progeny of the third generation of 
a species producing the lowest mentioned number of 
seeds is sufficient to cover the entire surface of the globe 
with plants, it is very obvious that a very small per¬ 
centage ever become plants at all. Their minuteness 
and the very little nutriment they contain precludes 
the idea that they offer great temptations to, and are 
destroyed by birds. Again we see that our native 
Orchids thrive admirably when they have succeeded 
in establishing themselves, a fact which suggests the 
idea that they either do not germinate or are killed 
in the process of germination or soon after. The 
length of time they require to complete this process 
must be fatal to their well-being in this our changeable 
climate, where the necessary conditions as to heat and 
moisture are too inconstant and variable to allow the 
seedlings to establish themselves ; whereas, the seed¬ 
lings of other plants are ready to spring into life and 
activity upon the accession of the proper degree of 
heat and moisture, those of Orchids are unable to do so. 
—J. F. 
-ox;-- 
A TOBACCO VAPORIZER. 
Me. Chakles Jolt, of Paris, who is always doing 
good suit and service to horticulture, by publishing. 
reports and notices of a useful character on all sorts of 
interesting subjects, has lately called attention to an 
invention by one of his countrymen, M. Martre, 15, Hue 
M. AIartre's “ Thanatcphore.” 
de Jura, Paris, for distributing the vapour of tobacco in 
plant houses. The “Thanatopliore” or tobacco vapor¬ 
izer, of which, thanks to M. Martre, we are enabled to 
give an illustration, has been designed to meet a want 
felt among continental growers, who have adopted the 
plan of filling their houses with the vapour of tobacco, 
instead of tobacco smoke. Horticulturists, in all times, 
have ever been desirous of adopting the most efficacious 
means of destroying the numerous insect parasites which 
infest their plant houses. To wash the leaves as is 
usually done is a long and tedious operation, and by 
this means one cannot always reach the pests, nor is 
the practice applicable to the flowers. Fumigating 
with tobacco is certainly effective to a great extent, but 
the process has its disadvantages in the injurious effects 
of the oxide of carbon, sulphuric acid, and other dele¬ 
terious gasses, which fill the house when the fire is 
introduced, if not very carefully done. All this to a 
great extent is avoided by the new method of vapour¬ 
izing the tobacco, by the means lately mentioned in our 
columns, and still more so by doing it with the 
“Thanatopliore,” which by being kept outside the house 
prevents anything but the vapour of Nicotine from 
entering. Air. Joly assures us that the process is a 
great improvement on all former methods. 
ORCHID NO TES AND GLEANINGS. 
The Orchid Growers’ Calendar. —With 
bright sunny weather comes an extra need for vigilance 
in looking after thrips, both black and yellow, and 
wherever they are known or suspected to be, the 
sponge and tobacco-water should be unceasingly used 
among the plants. Yigilance in keeping them down is 
great thing, for come they will, and bad work will the 
they make if not looked after. Soon even the Car¬ 
nation blooms outdoors will be covered with thrips, 
and we need not wonder or blame anyone if they appear 
in the Orchid-houses. If, however, the requisite amount 
of attention is given they may easily be kept under. 
In collections so unfortunate as to possess it a watch 
should at all times be kept for the Cattleya-fly and grub, 
illustrated in The Gardening "World, p. 588, vol. i., 
the fly especially being looked after in order to secure 
it before it can pierce the plant. Any suspiciously 
gouty-looking buds of Cattleyas (care being taken to 
make sure if they are bored or not) or gall-bearing 
points to roots should instantly be cut off and burnt. 
As a rule, it is easy to tell the injured buds, as they 
swell into a bulb-like form at the base, and show no in¬ 
clination to grow upwards in the usual way. These 
gall-making insects are a great pest, and as one or two 
collections having them have been lately distributed, 
we may be sure they will appear in fresh places. This 
word of warning, therefore, will not be out of place, as 
they are to be exterminated if taken in the early stage, 
but terrible to deal with if once allowed to establish 
themselves.— James O'Brien. 
The Orchids at Manchester.— If we were to 
search Great Britain over at any season of the year, it 
would be well-nigh impossible to get together such a 
truly grand display of Orchids as has heen on view in 
the Botanical Gardens at Old Trafford during the past 
week. They were essentially the leading feature of 
one of the best exhibitions the Manchester Botanical 
and Horticultural Society has had since the Whitsun¬ 
tide series was commenced nineteen years ago ; and 
than the magnificent examples staged by Air. George 
Hardy, of Timperley, probably nothing finer has ever 
been seen anywhere. Air. Hardy showed in five classes, 
and scored four firsts and a second, an achievement of 
■which'both he and his clever gardener, Air. J. Hill, 
have every reason to be proud. Air. Hardy’s first prize 
collection of fifteen will long be remembered by the 
Orchid fanciers who saw the plants, and they worthily 
held the post of honour in the new show house. The 
collection comprised Odontoglossum vexillarium, a 
sheet of blooms 3 ft. over ; Dendrobium Wardianum, 
with fourteen long spikes of flowers ; Dendrobium 
Paxtoni, 5 ft. through, and nearly as high, and 
superbly bloomed ; Lselia purpurata, with a dozen 
spikes ; Odontoglossum vexillarium roseum, 2 ft. over, 
remarkably fine ; Cattleya Alossise, 3 ft. in diameter, 
a dense mass of flowers ; Yanda suavis, with seven 
spikes ; Cypripedium superbiens Yeitchii, with twenty 
blooms ; C. caudatum, with eight fine flowers ; Aerides 
odoratum, a good mass ; Cattleya Alendelii, a grand 
plant with fourteen flowers ; a splendid mass of 
Cypripedium Lawrenceanum ; a good Dendrobium 
suavissimum ; and Cypripedium Stonei, with six 
spikes, a wonderfully beautiful plant. The second 
prize was taken by Air. J. Cragg, gardener to A. Heine, 
Esq., Fallowfield, who is coming to the front in good 
style, but was rather weak in this class, having thrown 
his strength into the next class, for nine. Mr. A. Cole, 
gardener to J. Broome, Esq., Didsburv, was third. 
The leading collection in the class for nine, set up 
with good judgment by Air. Cragg, included a grand 
specimen of Calantlie veratrifolia with twenty-one 
spikes ; a Cattleya Alossire, nearly 5 ft. over, with 
about 125 flowers, a splendid mass ; a very fine C. 
Alendelii ; Dendrobium Devonianum, a wonderful mass 
of spikes, 4 ft. through ; Dendrobium Paxtoni, 5 ft. 
high and 4 ft. through, splendidly bloomed ; a remark¬ 
ably good mass of Cypripedium Lawrenceanum ; and a 
mass of Odontoglossum crispum, 4 ft. through, but 
horror of horrors made up of all sorts of varieties. The 
leading plants in Air. Hardy’s second prize group were 
a beautifully-bloomedpiece of Dendrobium Jamesianum, 
a glorious mass of Odontoglossum vexillarium roseum, 
4 ft. in diameter, Cypripedium Farishii, with eleven 
spikes, and a splendid mass of Alasdevallia Harryana. 
Air. Elphinstone, gardener to John Hey wood, Esq., 
Stratford, was third, with a neat collection of small, 
