ON FERNS. 539 



June and July. It should be gradually reduced from August until 

 November, when a minimum temperature of 55deg. at night is all 

 that is required, and it need not be much higher during the 

 day until March again, when the vegetation commences. It is 

 important that no Ferns whatever should be placed in close 

 proximity to the hot-water pipes, which should be so disposed 

 as to be completely hidden from view by the rockwork, and the hot- 

 air shafts should be so managed that the heat generated by the 

 pipes may not come in direct contact with the plants, but diffused 

 in the house by passing through and at the back of the rockwork. 



Ventilation. — The ventilation of the exotic fernery, whether 

 as a stove or as a warm greenhouse, is of great importance, 

 and proper means of renewing the air at the required times 

 should be provided for in the building of the structure. Venti- 

 lators in the roof of the house are not sufficient, for when they 

 are opened a cold current at once rushes in, and results in the 

 discoloration of the foliage, which is due to the condensation 

 upon the fronds of moisture caused by the cold current. The 

 ventilation should be managed so that a free and constant supply 

 of fresh air may be admitted without creating a regular draught, 

 which is injurious to all plants, but particularly so to Ferns of 

 any and all kinds. To that effect provision should be made, 

 not only for the escape of hot air at the top, but also for the 

 admission of fresh air along the lower part of the house by 

 placing ventilators along the sides. These should be disposed 

 a little below the level of the hot-water pipes, so that the air, 

 which before escaping through the top ventilators, passes over 

 and among the plants, should only do so after having been 

 slightly warmed by a temporary contact with the hot-water pipes. 

 Through this arrangement an upward current, which prevents 

 chilly down-draughts, is produced, and the health of the plants 

 •subjected to this treatment is shown by a sturdy growth, and 

 the production of a harder and more enduring foliage than is 

 the case when the fernery is subjected to the influences of a 

 high temperature combined with heavy shading, an abundance 

 •of permanent moisture, and a lack of ventilation, which is con- 

 ducive to the production of weak and elongated foliage only. It 

 is needless to add that the ventilation should be carefully attended 

 to, and only when the temperature is high enough, and the 

 exterior temperature and state of the atmosphere admit of the 

 change of air, in which case the ventilators should be open as 

 •early in the morning as possible, and left on as long in the 

 afternoon as it is considered safe; The Ferns which require the 

 greatest amount of ventilation are the Cheilanthes, Nothochlsena, 

 and Anemia {Anemia tomentosa, Fig. 339). 



Ferns in Pots — Repotting. — All that has been previously 

 recommended in connection with light, soil, temperature, shading, 



