10 THE ORCHID REVIEW, (JAN.-FeB., 1919. 
And there are other blue Orchids in the southern hemisphere, among the 
Australian, Thelymitra and Caladenia particularly. Fitzgerald, for example, 
figures no fewer than eleven Thelymitras to which alone the term blue can 
be applied, and if any hybridist can raise among tropical Orchids a blue of 
~ the brightness and purity of colour of Thelymitra crinita, Caladenia 
gemmata or C. coerulea, there will be no need to apologise for its presence 
in his collection or to exercise a little imagination when attempting to 
describe the colour, Australia is surely the headquarters of blue Orchids, 
and as we have readers there who are quite familiar with them we hope they 
will oblige with a few notes. R.A.R. 
By J. T. BARKER, Orchid grower to His Grace the Duke of 
| CALENDAR OF OPERATIONS FOR JAN-FEB. 
Marlborough, Blenheim Palace, Woodstock, Oxon. 
OW that the great struggle of nations has ended, we as cultivators have, 
in many cases, to bring our collections back to pre-war excellence, for 
the difficulties that everyone has had to contend with made ravages among 
the plants. Although the strife is over, things are still far from normal; 
but we can now look forward with confidence, knowing that in the near 
future we shall have the satisfaction of seeing our plants well cared for, and 
regaining their old vigour. — 
TEMPERATURES.—The most suitable temperatures for the different 
departments are as follows :— 
Cool house: Day 50° to 55°, with sun 60° ; night 50°. 
Intermediate house: Day 60° to 65°, with sun 60°; night 57° to 60°. 
Cattleya and Mexican house: Day 60° to 65°, with sun 68°; night 58°. 
Stove or East Indian house: Day 65° to 70°, with sun 75°; night 65°. 
At this season it is well for the inmates of the houses if quiet tempera- 
tures are kept, as should any effort be made to push the plants into growth, 
a check may be given them during a spell of cold weather. Plants will not 
suffer from the temperatures running down a few degrees during severe 
weather, providing that the atmosphere and the plants are in a dry state. 
Another important point is that the lowest temperatures in the houses 
during the twenty-four hours should be in the early morning, with a gradual 
rise till mid-day, and then a gradual fall till the night temperatures are 
reached. A rise of 5° between the morning and mid-day temperatures will 
be ample, but with the influence of sun heat a further increase will be 
beneficial. 
ATMOSPHERE.—Owing to the amount of fire-heat necessary at this 
it is quite easy for any house to acquire a stuffy condition, unless 
fresh air 1s given daily. Where a good system of bottom ventilation is in 
