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, 

 Neottopteris, 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 



