August 5, 1899. 
THE GARDENING WORLD 
777 
irritation, which causes the production of cells, 
which form the warts which you find on your plants. 
After the larvae have fed for some time they change 
to the pupae state, which is passed in the soil. The 
life cycle is complete in two months. The later 
broods from the weevils hatch out and the larvae or 
first stage after the egg pass the winter in the gall. 
The galls, as a rule, sooner or later decay, and may 
thus be the ruin of the plants. 
Remedies. —Keep the land clean, especially keep 
it free from cruciferous weeds. Destroy the first 
attacked plants, also all old Cabbage stocks. 
Applications of gas-lime after clearing off the crops. 
Avoid using vegetable mould as dressings to the 
land. 
——-So-—■ 
CROSS-BRED POLYPODIES. 
Whether hybridisation or cross-breeding of Ferns 
is the subject in hand, we may say at once that it is 
difficult, if not impossible, to do the work with that 
certainty which is accomplished amongst Orchids. 
The hybridist or cross-breeder can only hope to 
bring the protballi of two parents into contiguity 
and hope for the best. The archegonia (female cells) 
and the antherozoids (male cells) are too small to be 
CONFERENCE ON HYBRIDISATION. 
(Concluded from page 762.) 
In the unavoidable absence of Dr. W. O. Focke, of 
The University, Bremen, on the second day of the 
Conference, which was held in the Town Hall, 
Westminster, the chair was taken by the Rev. Prof. 
Geo. Henslow, M.A, who said there was no 
necessity for a long introductory speech, as the 
time would be fully occupied with the papers to be 
read. He then briefly introduced Herbert J. 
Webber, Esq , Washington, U.S.A. 
Plant Hybridisation in the United States. 
Herbert J. Webber, Esq, Washington, U.S.A., 
special envoy from the U.S. Department of Agricul¬ 
ture, gave a very interesting lecture on the work 
being done by the United State Department of Agri¬ 
culture in plant hybridisation, illustrating his re¬ 
marks by limelight views. He said the work of his 
department had not been long under trial, to that as 
yet he could give no definite results. Their cross¬ 
breeding, &c., was chiefly among the Orange plants, 
Cotton and Cereals. Among the OraDges, he stated 
their aim to be to secure a hardier variety or varieties, 
for both last year and this a great many plants had 
been spoilt by frost in a single night, causing losses 
all through, however, was towards the diminution 
of the lateral lobes. The characters of the leaf- 
blades were often found to be completely altered. 
The hybrids showed in all cases increased size and 
vigour. The Tangierine OraDge was, in cases, the 
male, and the trifoliate was the female. In time, it 
is hoped to get ihe qualities of a good market fruit. 
Experiments are also being made between Citrus 
Aurantium and the Pomelo (C. decumana). The 
primary results in these trials gave nearly all true 
Pomelos, although proper hybrids were found. 
Pineapples have been taken in hand, and some¬ 
thing like 1,000 are now developing. The object in 
view here is to get seeded fruits. By crossing varie¬ 
ties or species usually seedless seeds are found in 
those operated with. Mr. Webber also said that the 
disease-resisting qualities of the Pineapples were in 
need of attention. They were also working to 
obtain smooth-leaved Pineapples, because of the in¬ 
convenience attending the work with the present 
forms. 
The Sea-Island (off Georgia) Cotton, which is a 
species with very fine long threads, yielding, in fact, 
the best Cotton in the world, was under trial with 
the Upland Cotton. The Sea-Island Cotton is being 
used as the male parent, and it is found that to be of 
12 34 
I, POLYPODIUM VULGARE BIFIDO-CRISTATUM ; 2, P. V. ELEGANTISSIMUM CRISTATUM ; 3, A REVERSION FROM No, 2 I 
4, P. V. ELEGANTISSIMUM. 
observable except under the power of the micro¬ 
scope. The form of the progeny and their general 
behaviour is almost the only clue upon which the 
Fern raiser can rely 
The accompanying illustration was prepared from 
dried specimens of plants in his collection, shown at 
the Chiswick Conference by Charles Thomas 
Druery, Esq , F.L.S., xi, Shaa Road, Acton, 
Middlesex. The supposed parents are Polypodium 
vulgare var. bifidc-cristatum and P. v. elegantissi- 
mum,shown on the extreme left (i) andright (4) respec¬ 
tively. The two fronds in the middle of the picture 
are believed by the raiser to represent the progeny. 
The finely cut frond (2) is considered to represent the 
true cross,while the frond (3) muchdivided at the base 
only is believed to be a reversion towards the 
parent on the left. We describe the variety P. v. 
elegantissimum cristatum as a cross, because varie¬ 
ties only of the Common Polypody are concerned. 
The Buds and Berries of Myrtus Communis- were 
eaten by the Ancients in lieu of spices, and are still 
used in parts of Tuscany in place of pepper. A wine 
called Myrtidanum is also prepared from the plant. 
Coming nearer home, in France, an agreeable 
perfume known as Eau d'Ange, is distilled from the 
flo wers,—L indley. 
up to as much as hundreds of dollars. The view was 
put forth that unless a hardier and equally sweet 
Orange can be raised, the growing of these plants in 
Florida at least, must be given up. Citrus trifoliata, a 
deciduous, trifoliate plant grows well as far north as 
New York, and this, crossed with The common 
Orange and others, was hoped to yield a fruit after 
their desires. 
If, said Mr. Webber, we could get some of the 
common Orange blood into the trifoliate variety (the 
common Orange is unifoliate and not deciduous) the 
characters of hardiness and earliness might be 
secured, two things greatly for the better, we think. 
In all the species of Orange and several of the 
Citrons or Lemons we find poljembryony, that is, 
several plants are raised from one seed. The lantern 
was here requisitioned to more clearly explain and 
demonstrate the development of superembryony. 
The illustrations represented hybridisation between 
the Tangierine Orange and the three-leaved (tri¬ 
foliate) tribe ; and the latter and the sweet Orange. 
These experiments, it was well to bear in mind, were 
between evergreen and deciduous species. 
The results, as shown, proved true hybrids and 
“ false hybrids ” coming from the same seeds; and 
very decided differences in the heights, habits, and 
forms in a single batch of seedlings. The tendency 
any good a smooth-seeded Upland Cotton must be 
chosen as the bearer, because that with rough seeds 
the fibre gets spoilt in the jennying process during 
manufacture. 
The Structure of Certain New Hybrids. 
The lecture by Dr. J. H. Wilson, F.R.S.E., St. 
Andrews, N.B., on "The Structure of Certain New 
Hybrids (Passiflora, Albucas, Ribes, and Begonias 
&c.),” with lantern demonstrations, was highly inter¬ 
esting, and very full of instruction and suggestion. 
He had crossed Passiflora caerulea (fivelobed leaves) 
with P. Buonapartea (leaves entire), and the result¬ 
ing hybrid showed a three-lobe-leaved plant. The 
lecturer made a neat arithmetical solution of this by 
saying that if we add up five and one we get six, 
which, divided by two, gives us three. The perianth 
of this hybrid is remarkable in having the three 
colours, red, white, and blue. Dr. Wilson went 
much more minutely into the details of structure in 
his hybrids than did any of the other lecturers. He 
showed by the aid of the lantern where the 
parents differed from their progeny, and emphasised 
the need for far greater accuracy of observation, 
even to the microscopical details of the results 
attending hybridisation. He also showed peculiari¬ 
ties in the structure of the ovaries of the above 
