68 
THE FERN WORLD 
being so built up and disposed as to leave room here and 
there for a foothold. If all the pockets and interstices were 
then filled in with proper soil, it would be found that our 
native Ferns, carefully planted in the sides of such a dell, 
would thrive admirably, and without requiring, even in the 
severest winter weather, any protection against frost. The 
gently outward sloping form of the cavity would admit the 
rain, which would fall equally upon the surfaces of the jutting 
ledges of rocks. The path leading into such a subterranean 
cutting could be sloped gradually down at either end from the 
ground level to the bottom of the dell. If such a subterranean 
fernery were covered with glass, it would become sub-tropical, 
and the most delicate ferny growths could, during the 
summer, be grown in it ; whilst by the introduction of heat, 
by means of hot-water tubes running along and through it, 
winter protection would be afforded, and a truly beauti- 
ful winter-garden of Ferns could be maintained. Water 
would be best supplied, during dry seasons, by means of a 
fine rose attached to a garden hose, and, should the place be 
covered with glass, regular ventilation would require to be 
given, but with such care as would prevent an exposure of 
the underground fernery too long to the influence of a dry 
and heated atmosphere. 
