1 86 THE FERN PARADISE. 
in g in the perpetual moisture engendered under 
the mossy covering of the wall, had crept along 
until they formed a sheet nearly a foot square. 
Then, the atmosphere of the brook had wonderfully 
helped the vigorous growth of the plant. We took 
our specimens from their damp and mossy habitat — 
carefully preserved them during our stay in Devon- 
shire, by keeping them constantly moist — and then 
brought them to our London home. But we did 
not forget to supply as nearly as possible the 
conditions under which we found them growing 
in their natural home. Shade, moisture, and leaf- 
mould, are the three conditions of success for 
the Common Polypody. It requires no great 
depth of soil ; but that soil must be leaf-mould. 
We brought the leaf-mould from Devonshire with 
our little stock of Polypodies. Some of these we 
planted out in our rockery. All have succeeded 
to perfection. But the grand plant before us 
has exceeded our most sanguine expectations. 
All we did was simply to strew the bottom of a 
small seed-pan — nine inches wide by three inches 
deep — with broken pieces of flower-pot; upon that 
