58 
CHOICE BRITISH FERNS. 
tions in the ensuing growing season, and a plentiful crop 
of thrips and other abominations in the vermin way. 
A house such as this accommodates some 400 varieties, and 
is a delightful sight for the greater part of the year, while, 
even in the winter, the evergreen varieties make a refreshing 
show of verdure. At first we planted all the Ferns direct 
into the soil of the rockeries, but found it advisable, in many 
cases, to plant them in pots and sink them, thus permitting 
re-arrangement when needed, either for the benefit of the 
plants or the sake of variety. 
In contriving a Fernery of this or similar descriptionj it 
must be borne in mind that coolness and shade are essential 
conditions of the well-being of the plants. These conditions 
can only be fully attained in a sunk house, built on the 
principle of the frame described in Chapter Y., and well 
protected from the direct rays of the summer sun. 
For the accommodation of the class of Filmy Ferns, of 
which the British representatives are the two forms of the 
Tunbridge Fern {Hymenophyllum tunbridgense and H. uni- 
later ale) and the Killarney Fern {Trichomanes radicans) and 
its varieties, still greater protection is required than is 
afforded by ordinary frames or conservatories. These ex- 
tremely delicate plants only grow, naturally, in the rocky 
beds of streams, where the atmosphere is continually satu- 
rated with moisture, and, in fact, where they are constantly 
bedewed with spray. Hence, a few minutes’ exposure to a dry 
atmosphere shrivels up their thin, pellucid fronds, and pro- 
longed exposure is fatal. To meet this state of matters baffled 
both the botanists of old who desired to transmit living 
plants from place to place, and the Fern-lovers who longed 
to cultivate them, until, at last, Mr. H. Ward circumvented 
the difficulty by the invention of what is now, and ever will 
be, known as the Wardian Case. 
This, as everybody, presumably, knows, is a glass, almost 
airtight, case, covering a receptacle for soil and drainage. 
The water supplied is prevented from escaping altogether by 
evaporation, since it is condensed upon the glass, and runs 
down to the soil to be evaporated again ; hence, the air and 
