JANUARY, 1918.] THE ORCHID REVIEW. 13. 
ATMOSPHERIC MOISTURE is used to counteract the artificial heating of 
the houses, and the amount must be regulated according to the amount of 
heat necessary to maintain the temperatures. The outside conditions of the 
atmosphere will have a bearing on this matter, and in damp weather much 
less will suffice than when the sky is clear and bright. Atmospheric 
moisture is necessary to the plants’ growth, and to prevent attacks of thrip 
and other insect pests. It is applied by damping the floors, the staging 
between the plants, and in fact everywhere except the plants themselves, 
and is termed damping down. 
WATERING, or the application of water to the compost, is practically 
the whole secret of plant cultivation in glasshouses. It is impossible to 
define the amount of moisture each individual plant should receive, but a. 
safe line to draw is as follows :— 
All growing plants should have water applied to them whenever they 
become dry, whilst those at rest should on no account be allowed to shrivel. 
Excess in eithér direction is equally injurious. 
CATTLEYAS AND ALLIES.—Cattleya Percivaliana and Triane, with their 
hybrids, are developing their flowers, and should be given a light position. 
It is possible, with the many lovely hybrids now in existence, to produce a 
display of these plants in the dull dark days of winter, which years ago- 
would have been considered adequate to the bright days of summer. 
LA&LIA ANCEPS AND ITS VARIETIES, as they pass out of bloom and 
commence to push new roots, may be repotted as advised last month. 
Ca@LocynEs.—C. cristata and its varieties have their flower spikes well 
advanced, and should be carefully watered, as an excess at the roots, or 
overhead, may cause them to decay. The rare C. Mooreana is a most 
lovely Orchid that produces its blooms at this season. It is easy to grow if 
treated much in the same manner as C. cristata, but prefers the warm end. 
of the Intermediate house. This genus must not be exposed to too much 
sunlight at any season, as their leaves readily scorch, especially if the plants- 
are at all dry. C. elata and C. ochracea are also pushing up their flower 
spikes, and require water whenever they become dry. Plants of C- 
pandurata, C. Massangeana, and others that have not as yet commenced to- 
grow must still be kept on the dry side. These beautiful plants, to my 
mind, deserve extended culture, as even the most modest of them are 
delightful objects when in bloom. 
Mittonias of the Brazilian section should be examined to see if any of 
the plants are in need of more pot room, or new material. It is necessary, 
perhaps, here to point out that a plant may want repotting without being” 
placed in a larger receptacle, through the compost becoming decomposed. 
In some cases a plant will deteriorate from causes not always apparent, 
and it will then be advisable to place. the plants in smaller receptacles so- 
