56 
THE FERN WORLD 
genial, then, not only are artificial means necessary for the 
protection of the plants, but constant care and watchful- 
ness are required, in order to prevent the discontinuance 
of the extemporized aids to growth. To those species, for 
instance, which require the constant presence of a still 
atmosphere, loaded with moisture, as do the Bristle Ferns, 
the Filmy Ferns, the Sea Spleenwort, the True Maidenhair, 
and others, a covering of glass serves to provide the nearest 
approximation to the natural conditions — furnished by 
the atmosphere of dripping cave, or clefts of dripping- 
rock — by retaining moist vapours over and around the 
plants. The artificial substitution of glass for the moist 
concavity of the dripping rock can take place in various 
modes, and upon a scale commensurate with the means at 
the command of the fern cultivator, or with the requirements 
of the plants themselves. Thus, the area to be artificially 
covered with glass may vary in extent from that of a small 
glen or valley, down to a little ‘greenhouse,’ or conserva- 
tory, or to a tiny Fern-stand under a shade or bell-glass ; 
and under all these coverings, by the artificial retention of 
moisture, and the artificial production and maintenance of 
heat in varying degrees, providing for the adoption as nearly 
as possible of natural conditions of growth, the most delicate 
and beautiful forms of Fern-life — both native and tropical — 
can be made to flourish. In the same way the hardier Ferns 
suitable for open culture in the out-door garden, can be 
treated. If rocks and streams exist on the grounds of the 
cultivator, no artificial protection and no watchful care will 
be needed to promote their growth. If the conditions of 
growth have to be extemporized, this can be done upon a 
large scale by the erection of huge rockeries, banks, and 
mounds, and by the introduction of running water, or upon 
the most moderate scale to suit the circumstances of the 
poorest cottager, who may have only a few square feet of 
