February, 1913.] 
THK ORCHID WORLD. 
hicolor was required, and the best results were 
obtained by mating the primary hybrid, C. 
Iris, with its parent, C. aurea, the result being 
C. Venus. 
C. aurea is the largest of the yellow section 
of Cattleyas, but the somewhat weak consti- 
tution of the species and the rather drooping 
nature of the petals does not allow us to call 
the plant perfect from a hybridist's point of 
view. It is to remedy these defects that the 
mating of the species with C. bicolor has been 
effected, and with what beneficial results 
everyone is well acquainted. 
DENDROBIUMS. 
DENDROBIUMS form one of the chief 
supplies of bloom during the month 
of February. When the buds com- 
mence to open care must always be exercised 
with regard to the atmospheric moisture of 
the house, an excess tends to produce spotting 
of the flowers, especially when the night 
temperature is low. The heat of the house 
may be economised at night-time by covering 
the glass with mats or blinds, and by this 
means less heat in the pipes will be required. 
Plants invariably grow better when the neces- 
sary temperature can be maintained without 
much artificial heat. 
Where many Dcndrobiums are grown it is 
a common practice to bring a few plants into 
extra heat in order that they may open their 
flowers before the remainder of the stock. 
These early flowers are not always equal in 
quality to those of later date, but they prove 
useful by extending the flowering season. 
Plants which have been forced in this way 
are very apt to recommence growth at an 
early date, even before the necessary cultural 
atmosphere has been prepared, consequently 
they will require frequent watching or the 
young growths will very likely damp off. The 
best plan is to remove these early flowered 
plants into a cool and dry atmosphere where 
they may be induced to continue resting for 
a few more weeks. 
Most Dendrobes look their best when 
grown into specimens bearing a hundred or 
more flowers, and a house of such plaiils is a 
magnificent sight. ihc best and (juickcst 
method of obtaining large plants is to grow 
the small ones on as rapidly as possible l)y 
not allowing them to flower, or by removing 
the flowers directly they open. As soon as a 
plant has six or more good bulbs the rhizome 
should be severed at a place that will allow 
two or three bulbs to support each leading 
growth. In this way additional new growths 
will be produced from eyes which would 
otherwise remain dormant. The plant, or 
roots, should not be disturbed in any other 
way, unless repotting is necessary, an 
operation best deferred until root action 
recommences at a later period. 
It is surprising to see how well Dcndro- 
biums grow in comparatively small pots, an 
excess of compost appearing very injurious 
to them, and frequently resulting in rapid 
decline of their health. .Small propagated 
plants should be placed in pots just large 
enough for an additional bulb to be made. 
The following season more room may be 
given, although it will hardly ever be found 
necessary to allow more than two inches of 
space between the new growth and the rim 
of the pot. All the bulbs should be neatly 
tied to a central stick, and whenever insect 
pests make their appearance never fail to 
destroy them at the earliest opportunity. A 
suitable compost will be found in a mixture of 
one-half fibre, the other half sphagnum moss 
and a few chopped leaves. 
At the commencement of the new^ growth a 
minimum temperature of 55 aegrees will 
suffice, but later on, when the growing season 
is more advanced and frequent syringing of 
the plants is effected, 65 or more degrees will 
be necessary. Bright sunshine will cause a 
rapid and temporary rise of the temperature, 
but apart from this the cultivator should aim 
at a moderate increase of the heat week by 
week as the plants increase in the vigour and 
size of their new bulbs, the highest tempera- 
ture being when the bulb has almcst com- 
pleted its growth. From then onwards 
gradual lowering should occur until the 
minimum autumn temperature of 55 degrees 
is reached. When the plants have entirely 
