CULTIVATION. 843 



and syringing, the latter being the only remedy for 

 the black mildew. 



This concludes my observations on pot-cultivation, 

 and in order to save repetition, it must be understood 

 that the process as regards soil, watering, airing, &c., 

 is equally applicable to natural cultivation, which I 

 now proceed to describe. 



III. Natural Cultivation. 



THE natural cultivation of Ferns consists in growing 

 them without the aid of garden-pots. This is 

 accomplished by placing them, as far as artificial 

 appliances will permit, under conditions and influences 

 analogous to that of their native wilds ; for that 

 purpose uneven irregular surfaces are best adapted, 

 whether natural or artificially formed ; and as Perns 

 are generally called rock-plants, which many truly are, 

 therefore, in order to imitate rocks, the surface on 

 which they are grown is made irregular and covered 

 with rude stones, on or between which the Perns are 

 planted; hence the term Eoekery is appHed to this 

 kind of cultivation. 



For all species of Ferns, either hardy or tender, 

 this system of culture, which admits of their being 

 planted out, is far preferable, to whatever extent it 

 may be desirable to practise it, whether in the sheltered 

 nook, in the open air, or in stoves or greenhouses, 

 either partially or entirely devoted to it. For by it is 

 the finest health imparted to the plants. The rockery 

 bank which once occupied the Temperate Fern House 

 a.t Kew, together with the fine fronds of tropical species 

 grown on rockery in the Palm House, aflbrded excellent 



