CULTIVATION. 
373 
hot-water pipes. For the latter purpose, in small 
houses, temporary stoves of gas and charcoal are used, 
often to the utter destruction of the plants. 
To assist in maintaining a moist atmosphere besides 
the usual moist surfaces of the pots, it is desirable 
to have water-troughs on the top of the hot-water 
pipes, as also to place pans of water on or near the 
pipes ; also in hot weather, the paths and other 
evaporating surfaces should be wetted every morning 
and evening. An occasional syringing may be given, 
which should be done when the out-door air is charged 
with vapour; wetting plants when the air is dry 
causes a sudden evaporation, and a reduction of 
temperature on the surface of the frond is the con- 
sequence. This is especially the case with broad, 
smooth, glossy species, such as the genera Phymatodes , 
Neottojpteris, Asplenium, Diplazium, &c. ; occasionally 
the whole of some fronds or part of a frond becomes 
black. In order to raise vapour, a practice prevails 
with many cultivators to throw water over the hot-water 
pipes (or flues) ; there is no objection to this, pro- 
viding the air out of doors is warm, but in the winter 
season it is often done in the evening, in order to 
counteract the dryness of the air, caused by the extra 
heat of the pipes required at that season ; the house then 
becomes filled with hot vapour, which coming in 
contact with the glass of the roof condenses and falls 
in a shower of cold drops on the plant ; at the same 
time the temperature of the house rapidly falls, thus 
causing black fronds, spots in orchids, and such-like 
complaints. 
Ferns, like other plants, are liable to be more or 
less infested with insects; the soft membraneous kinds 
