4 
THE GARDENING WORLD. 
£ January 7, 1905. 
tage in height, weight, constitutional vigour, and fertility over 
the self-fertilised offspring from one of the same parents. 
Attention has been called by Willis to three factors in the 
gain resulting from cross-fertilisation, viz. : (a) Fertility of 
mother plant; (b) vigour of offspring, and (c) fertility of off¬ 
spring. The relative value of these factors vanes with dif¬ 
ferent plants. In the Carnation, for instance, factor (a) of cross- 
fertilised plants was 9 per cent, greater than in self-fertilised 
plants, (b) was 16 per cent, greater arid (c) was 54 per cent, 
greater. Even when the fertility of the mother plant is greatly 
reduced bv hybridising with a distinct species and the hybrids 
themselves are sterile or very unfertile, they nevertheless often 
show extraordinary vigour, that is (b) is often greater in 
hybrids than in pure-bred plants, but factors (a) and (c) are 
usually less. In plant breeding the importance of this in¬ 
creased vigour is very great. 
When a hybrid possessing desirable characters is produced 
from plants propagated by seed, it is almost invariably neces¬ 
sary to render these characters hereditary by careful selection 
and in-and-in-breeding. Darwin says : 
| Florists may learn . . . that they have the power of 
fixing each fleeting variety of colour if they will fertilise the 
llowers of the desired kind with their own pollen for half a 
dozen generations and grow the seedlings under the same con¬ 
ditions. But a cross with any other individual of the same 
variety must be carefully prevented, as each has its own 
peculiar constitution. After a dozen generations of self-fer¬ 
tilisation it is probable that the new variety would remain 
constant even if grown under somewhat different conditions. 
When a desirable hybrid is produced, it should be fertilised 
with its own pollen, the seeds thus produced planted, and the 
seedlings selected which most perfectly show the characters 
which it is desired to fix, after which these selected seedlings 
should be inbred and a third selection made, and so on, until 
the desired characters are produced true in all the seedlings. 
In case a desirable hybrid is found-to be sterile to its own 
pollen, it should be fertilised, if possible, with pollen taken 
from similar hybrids showing the same variation. 
In the continual self-fertilisation practised in fixing variar 
ti'ons there is doubtless much loss of vigour. In some cases 
this might be avoided by making numerous hybrids between 
several different sets of individuals of the same sort but not; 
closely related (that is, separated by numerous seed genera¬ 
tions), so that several unrelated hybrids, showing practically 
the same combination of characters, could be obtained. These 
hybrids could be bred together and rigidly selected each gen¬ 
eration, until all the seedlings produced show the desired com¬ 
bination of characters. However, in order to avoid the greater 
possibility of losing the variation, it is probably best in all 
cases to self-fertilise, if possible, a portion of the flowers. 
There is evidence which shows that odourless plants have 
been rendered fragrant by hybridising with scented species or 
varieties. According to Wittrock, Pansies have been consider¬ 
ably improved in this respect by crossing various sorts with 
the fragrant V. cornuta. Violetta, a fragrant sort, was pro¬ 
duced by crossing V. cornuta with pollen of the Pansy Blue 
King. Sensation, another scented variety, was also produced 
by crossing V. cornuta and the Pansy. Wittrock, who is 
probably the best authority on Violets and Pansies, says: “ No 
pains have been spared of late by the Pansy cultivators of 
Great Britain to increase the charm of the Pansy by obtaining 
perfume as well as beauty, but by a more extensive use of 
the odoriferous alpine species (V. cornuta L. and V. lutea, 
Huds., var. grandiflora (L.) Vill.) for hybridisation doubtless 
much may still be done in this direction.” 
There is a host of other instructive information in the 
various pamphlets named, which are available, we presume, to 
those interested.—“ The Florists’ Exchange.” 
Stormont Fruit-growers’ Association.-*—T he first annual 
meeting of the above association was held recently, and well 
attended. The secretary and manager submitted a statement 
of the year's transactions, which was considered highly satis¬ 
factory, and adopted. 
Some Useful Plants for Christmas Flowering. 
Where there is a demand for Christmas flowering plants and 
forethought has been given to striking, potting, pinching, etc., 
it is surprising wiiat an amount of good flowers may be 
obtained at this season of the year; and considering the dull 
and deserted aspect of things outside, perhaps there is no 
season in the year when the houses give so much pleasure as 
this. 
Chrysanthemums—the late-flowering sorts—are still in 
their prime. Plants of W. H. Lincoln, Souvenir d'une Petite 
Amie, Mdme. Cal vat. Surprise, Garnet, Minerva, Niveus, 
Tuxedo, Miss M. Blenkiron, Mdme. R. Cadbury, Joseph Brooke, 
Mine. L. Zede, Major Bonnaffon, Mrs. J. I. Tliornycroft and 
a host of others are still doing well. Princess Victoria and 
L. Canning are yet to come. These varieties require rather 
more heat to bring them out to perfection, especially the 
latter, which can be had in perfection as late as February and 
March. 
Salma grandiflora is especially striking this time of the year, 
and will continue to bloom for a length of time if properly fed 
and attended to. Primula obconica is veiy useful, too, at this 
time of the year, it being an excellent vase plant, and as cut 
flowers arranged with suitable foliage it is extremely pleasing. 
So also are the double Primulas. These seem to be much 
neglected. One wonders why, considering to what uses they 
may be put. Christmas Rose Helleborus niger is very nice 
as a pot plant, and useful for cutting. Some still hold the 
view that these cannot be potted up to flower successfully, but 
we find they will stand it for several years in succession. 
Libonia floribunda is very pretty. Plants of this that have 
been grown in the open during summer and brought on gently 
in heat are now in full bloom. These form a striking contrast. 
Their lemon and red flowers, produced in such abundance, have 
a nice effect when staged; and as vase plants for house de¬ 
coration they are useful. Roman Hyacinths, Narcissus, Snow¬ 
flake, Lily of the Valley (retarded), Arum Lilies, Azalea mollis 
and A. Deutsche Perle- are in full bloom, as also Solomon's 
Seal (Polygonatum multiflorum). If home-grown roots of this 
are used they will require to be stood out in their pots until 
they have been frozen, when they will readily force if given a 
nice bottom heat. 
The warmer houses are yet gay with Begonias Gloire de Lor¬ 
raine and Tumford Hall, which are well known and now indis¬ 
pensable. Agatha is extremely useful, being dwarfer in habit 
than Gloire de Lorraine, and is capable of lasting over a longer 
season. The young growths continue to come up from the 
bottom and bloom. B. metalliea is a useful subject apart 
from the highly decorative value of its leaves. The flowers, 
produced in clusters well above the foliage, have a very pleas¬ 
ing effect. Gloire de Sceaux, another much neglected Begonia, 
has a double advantage of being decorative in its foliage and 
extremely pretty in its bloom. When staged with Coleus tliyr- 
soideus and foliage plants it is very striking, and seems per¬ 
fectly in season now. Abutilon Sawitzi is a useful plant. Cut¬ 
tings that were struck early in the year and pinched, make 
tine plants, throwing up their flowers now, which make a strik¬ 
ing contrast to the variegated foliage, and are much appre¬ 
ciated. Poinsettias and Euphorbia jacquiuiaeflora serve to 
brighten the stove as also do the Gesneras, a collection of 
which is well worthy of being grown. Careful watering and 
freedom from draughts are essential in growing these, 
rreesias are extremely useful now. Many gardeners 
still say these cannot be obtained to perfection so early. 
We find very little difficulty, providing they are potted 
early enough and kept growing; the first week in 
August suits them veiy well. Another very useful plant 
and one very appropriate for the season is Rivina humilis, 
whose red berries produced in -such abundance have a 
good effect when arranged with Begonias, etc., and as a table 
plant it is very effective. Rivina does best when grown in a 
stove temperature, using a compost of equal parts loam and 
peat with sufficient sand to keep the soil open. It should never 
be allowed to become dry, and is best when shaded from very 
bright sunshine. H. J. Pitman. 
