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DECEMBER, 1910.] THE ORCHID REVIEW. 359 
flower, and where they are grown in quantity will continue to make a good 
show and brighten the house. In fact it is like a ray of sunshine to see 
them in bloom. They should be kept well supplied with water until the 
flowers are off, but the base of the bulbs should not be dipped in the water, 
as it is liable to rot them at this season. 
Vanbas, Saccolabiums, Aérides and Angreecums now require very little 
water, and a sprinkling occasionally with a rose-can over the surface of the 
compost when very dry will be sufficient. It takes them too long to dry 
out at this time of year if they are given a good watering. Other allied 
genera require similar treatment. 
CULTURE OF ONCIDIUMS TO PREVENT THEIR 
DETERIORATION. 
MANY growers and amateurs do not cultivate the numerous species of this 
genus, which are suitable for Cool houses, owing to the fact that they 
cannot be kept long in a good healthy condition, and flowering successfully 
each year. However, from various experiments extending over three years, 
I can recommend the following course of treatment as being satisfactory in 
checking their habit of deterioration. 
In the first place, I like growing these Orchids on a shelf near the glass, 
either at the coolest end of the Intermediate house, or at the warmest end 
of the Odontoglossum house. In the second place, they should be grown 
in Orchid pans or pots, with a specially prepared compost, and repotted or 
repanned, as the case may be, every year, which should be done when the 
new growth is about two inches long. For compost use Polypodium fibre, 
sphagnum moss, well-rotted oak leaves, and a tea-spoonful of dry guano to 
a five-inch pot, mixing all well together. Place a layer of pure moss for 
surfacing the compost. 
Lastly, throughout the year, from the time that the new growths are 
two inches long till the flowers are open, water the plants with liquid 
guano once a week, and twice when the flower-spikes are pushing. 
If tested in the above manner, no signs of the deterioration, previously 
common to Cool-house Oncidiums, will be noticed. The plants I have so 
far experimented upon are Oncidium crispum, concolor, Forbesii, 
incurvum, tigrinum, and varicosum. A proof of the vigour possessed by 
these Oncidiums so grown may be seen from the fact that two years ago a 
plant of Oncidium tigrinum was allowed to bear two seed pods, and 
eighteen months after the same plant produced a spike carrying twenty-one 
flowers, and the new growth it is now making gives promise of being more 
vigorous even than the last. Oncidium concolor frequently produces two 
flower-spikes from each pseudobulb, which, I think, is unusual. 
ALWYN HARRISON. 
