206 PRACTICAL FLORICULTURE. 



in partial shade in a close, moist atmosphere. Hence it 

 is useless to attempt the cultivation of such unless they 

 are inclosed in cases in the dry atmosphere of an ordinary 

 sitting-room. The florist can easily adapt his green-house 

 to the proper conditions when required, but the amateur 

 must secure these by means of a closed case of some 

 kind. For single specimens or a few ferns and the like a 

 glass shade with a proper base of metal or earthenware 

 is frequently used, and is very ornamental. Ferneries of 

 this kind are sold at the principal horticultural and seed 

 stores. 



CHAPTER XXXI. 



FORMATION OF ROCK-WORK. 



This feature of pleasure ground decoration is generally 

 necessitated by circumstances; if the ground which has to 

 be chosen for that purpose is naturally stony, it often be- 

 comes the cheapest way to get rid of the stones, grouping 

 them so that they become ornamental. They may often 

 thus be used to advantage in forming breaks or screens, to 

 hide the flower garden from the vegetable or fruit garden ; 

 in this way they are laid up in rugged walls, the inter- 

 stices filled with soil and covered with hardy perennial 

 plants. Locations where rocks exist in their natural con- 

 dition can often be made highly interesting and ornament- 

 al by setting out plants of a drooping or trailing habit 

 (o overhang among them. Among those suitable for such 

 purpose are : 



Achilleas, of creeping growth, Linnasa borealis, 



Campanulas, of creeping growth, Lychnis grandiflora, 



Crucianella stylosa, Lysimachia nummularia, 



Cerastium tomeutosum, Orobus vernns, 



