due to the difference in light hours and that—if we could find a means of in- 
creasing our hours of light during the winter—gigas would present no more diffi- 
culty than any other Cattleya, particularly in the cooler climate of Sydney. 
Again, the terete species, Vanda teres, V. Kimballiana and V. Hookeriana, 
and the hybrid, V. Agnes Joachim are often shy bloomers here, whereas in their 
habitats, they flower prolifically. Here again, the secret lies in this matter of 
light. As far as I can ascertain, all those who have flowered these plants have 
either grown them out in the full sunshine or the plants have bloomed only when 
they have grown up through the roof of the bushhouse. 
So, if we have any Orchids which we find exceptional difficulty in flowering, 
it will pay us to consider closely how we are treating them in this matter of sun- 
light. If they are already growing in the sunniest part of the bushhouse, and 
have made good growth, it is possible that they are getting too much ‘light in 
summer, and it will probably pay to shift them into a more shaded part of the 
greenhouse during the long days of that season. If, on the other hand, they are 
in a shaded part of the house, then the obvious thing is to move them to a sun- 
nier place—making this move during the autumn or winter. 
_In any case, we should always increase the light available to our plants in 
the winter time, if possible, by removing battens or by otherwise decreasing the 
overhead covering. 
Another important feature of light is its relation to colour. It has been 
well authenticated that plants which flower in the high altitudes produce more 
brilliantly-coloured flowers than those of similar species which grow nearer to 
sea-level. This is attributed to the fact that in the high altitudes there is a 
greater amount of the ultra-violet rays in the light. I have had an experience 
with Vanda coerulea which, no doubt, has occurred to other Orchid growers. 
This plant grows on low shrubs and trees with plenty of sunlight, at altitudes 
ranging from 3,000 to 5,000 feet. Certain plants of this species flowered very 
shortly after arrival from India, the flowers being a deep blue in colour. Next 
year the flowers were still blue, but much paler in shade, while the third year they 
were almost white. Now, it seems that the so-called “dark” variety is found only 
at the highest part of the plant’s altitude range, whereas the paler hued types are 
found at the lower elevations. This seems to me to indicate that there is no such 
thing as an inherently dark-flowered or light-flowered variety of Vanda coerulea, 
and that the differences in colouring in the various plants are merely coincidental 
with the elevation and light conditions of their habitats. It seems to me, too, 
that much of the difficulty associated with the growing of this plant lies in the 
fact that we try to grow at an altitude of 15 to 20 feet a plant which is accus- 
tomed to the lighting and atmospheric conditions of 3,000 to 5,000 feet. 
Another experience of the changing of colour happened to me with a plant 
of Dendrobium Kingianum. The plant came from near the top of Mt. Cordeaux 
(about 4,000 feet), near Cunningham’s Gap, where I found it growing in a great 
mass upon basaltic rock. The blooms were a very deep crimson purple, definitely 
the deepest shade I have seen in the species. When it first flowered for me it was 
still a good, deep colour, but appreciably lighter in shade. Now, after five years, 
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