CULTIVATION. 863 



iLe higher part of the rockery is best suited for them. 

 In such a Fernery as this now before the mind's eye, 

 convenient positions, in the form of dripping crypts 

 and recesses, may be provided for the delicately beau- 

 tiful and easily grown Trichomanes and Eymenophyllum, 

 without the aid of glass cases that are necessarily 

 used, as already explained, under pot-culturo. 



Where Tree Ferns would be grown, the proper 

 situation for them is the lowest part of the house, in 

 the valley, where the greatest head-room would be 

 obtained, and most constant shade and moisture about 

 their stems, which will encourage the essential growth 

 of the aerial out-grown roots. The path in the valley 

 may be straight or winding between the Tree Ferns, 

 the intervening spaces to consist of raised mounds or 

 hillocks, to be planted with the smaller kinds of Tree 

 Ferns and other large-fronded Ferris. The different 

 species of Selaginella should occupy the intervening 

 spaces between the plants, which will add greatly to 

 the natural appearance of the whole and assist in pro- 

 moting a genial atmosphere. 



To whatever extent a house of this nature may be 

 carried for tropical Ferns, the same must be allowed 

 for the extra-tropical kinds, and being sunk, the 

 necessary amount of heating power required will be 

 just sufficient to keep out frost. Keeping the house 

 shut during the winter season, so as to maintain a 

 quiet, still atmosphere, greatly assists in repelling 

 frost, indeed for such houses ventilation is only 

 necessary to keep down high temperature during 

 summer; free admission is, however, beneficial when the 

 external air is still and moist, when even the tropical 

 division may be freely left open during the nights of 



