334 FERNS : BRITISH AND FOREIGN. 



the purpose of giving consequence and dignity to the 

 house, thus laying the foundation for conditions un- 

 favourable to plants. The shelves or benches may consist 

 of dark-coloured porous stone or rough slate, with an 

 edging of smooth slate two inches deep, so as to form a 

 shallow trough, which should be filled with dark- 

 coloured sand or fine-sifted coal-ashes, the whole 

 pressed down, so as to form a firm smooth surface, on 

 which the pots are to be arranged. By this means a 

 degree of moisture will be retained more congenial to 

 the plants than when standing on stone or slate. An 

 edging of about three inches of Selagirtella hortensis or 

 8. denticulata gives a neat appearance, and if allowed 

 to run between the pots, the whole becomes more con- 

 genial than a naked surface. White sand or broken 

 quartz is frequently used, but it soon becomes dirty, 

 and has a harsh and dry appearance. 



In the arrangement of the plants some degree of 

 order must be observed, so that every specimen plant 

 of a species should be seen to advantage, and if the 

 collection is extensive, and the house has different 

 aspects as regards light and shade, then it is desirable 

 to arrange the plants according to their habits and 

 requirements ; thus, at Kew, the division Eremobrya 

 occupy the whole of the south side of the house ; this 

 division being less sensitive to the effects of the sun 

 or deficiency of water than the more extensive division 

 Desmobrya, which, on account of their thin texture, 

 very quickly suffer from dryness or too much exposure 

 to the sun ; therefore the north side of the house is 

 best for them. 



The natural direction of the fronds is the most 

 pleasing, whether upright, pendulous, or spreading. 



