PARK AND CEMETERY. 
235 
ROYAL BOTANIC GARDENS, KEW, SURREY, 
ENGLAND. X. 
FILMY FERNS. 
Among ferns, the filmies have special interest. Tall 
Dicksonias, Alsophilas and Cyatheas are not uncommon 
but it would be interesting to know if any Filmies are 
cultivated in the United States. Through the munifi- 
cence of a London surgeon, Kew largely owes the ex- 
tent of its collection. Dr. John Cooper Foster was said 
to have been the most successful cultivator of these 
plants in England. Fie made a special study of their 
requirements and grew them both on the roof and in the 
rooms of his London dwelling. “Filmies” is an appela- 
tion confined to three 
genera. Hymenopyl- 
lum, Trichomanes and 
Todea — the principal 
distinguishing charac- 
ter, botanically, of the 
two former is that Hy- 
menophyllum has a 
two valved involucre 
anil in Trichomanes it 
is united into a cup. 
Principal among the 
requirements necessary 
to perfect < uitivaiion 
are : ( 1 ) a humid at- 
mosphere charged to 
saturation point, (2) 
no direct sunlight, (3) 
no draught nor 
drought. 
Fronds so delicate 
and thin a s t o be 
translucent cannot endure a dry air — they grow naturally 
near brooks; in caverns or even in a place of oc- 
casional drip. They grow well when the condens- 
ation settles and remains in a profusion of dew 
drops on the foliage, and yet they dislike sy- 
ringing, except perhaps in Ireland. Subterranean 
caverns and cases within the greenhouse are two 
methods that insure humidity and equable temperature, 
the first a resort of Messrs. Backhouse at York, the sec- 
ond that usually adopted and the one in vogue at Kew. 
This class of plants are intolerant of direct sunlight. 
They must have light and do not want continual shade, 
nevertheless demand reflected or refracted light. The 
difficulty increases with the rising of t h 2 out-door tem- 
perature toward summer. The dryer the atmosphere 
the cooler can the temperature be maintained but 
draughts increase proportionally. It is to be remem- 
bered that the majority of these ferns are “cool” grow- 
ing and some will even withstand several degrees of 
frost. 
An atmosphere continually at saturation point is 
governed by glass cases inside the houses. If water is 
liberally sprinkled on the exposed surfaces within the 
case without wetting the foliage little difficulty is experi- 
enced in that direction. By vigilantly keeping the tem- 
perature low and the atmosphere humid in the house, the 
possibility of creating the ideal environment for the'plants 
in the cases is markedly increased. Avoiding direct 
sunlight, however little or weak, is of paramount impor- 
tance at all times. Naturally the question is: IIow can 
one keep a low temperature that is also humid and with- 
out draughts during the hot summers? That’s the diffi- 
culty in growing filmies. Dr. Foster never gave his 
plants ventilation beyond that obtained while they were 
receiving maintenance attention. lie maintained a cool 
atmosphere by having a stream of water continually 
playing on the outside of the house, thereby cooling the 
iron and woodwork and consequently the air; in South 
Africa the houses are opened in the early morning, the 
cool air admitted and 
the houses then closed 
for the remainder of 
the day ; at Kew the 
grooves in the walk 
formed by the beveled 
edge brick are kept 
filled with water and 
the walls, ceilirgs, un- 
der the stage and all 
exposed surfaces liber- 
ally and frequently sy- 
ringed, a very effective 
method for holding 
down the temperature 
and at the same time 
insuring a high per 
cent, of saturation. In 
balmy Ireland the dif- 
ficulty is too slight to 
require any special 
treatment. 
Drainage must be perfect, the soil contain little or 
no humus and if the peat has fine fibre with part of the 
peat .-oil shaken out it is better than either course or- 
chid peat or the peat without fibre. Depth in drainage 
is immaterial, the object is to have that provided per- 
fect. Supposing it is to be brick bats and potsherds, 
the top is covered with a three inch layer of peat sod 
intermixed with large pieces of charcoal. On this, small 
bits and large and well formed pieces of white sandstone, 
the whiter the better, since the deeper red the greater 
proportion of iron they contain and our purpose is to 
shun ron in this connection. A mere sprinkling of peat 
over the rocks will suffice in the way of organic plant 
food for any sustenance the plant may need. If the 
plants are purchased in pots they may be turned out, the 
drainage removed and then placed on the rocks, filling 
in around the sides with peat and finely broken sand- 
stone to give it compactness. When water is necessary 
it is applied to the stone anil capillary attraction brings 
it to the roots of the plant. Should the depth of the 
soil in which the plant has been growing be too great, 
transplanting imperfect or in any other manner should 
the water fail to reach the roots in the soil it must be 
applied directly by saturation. 
Under Ilymenophyllum and Trichomanes about 25 
genera are constituted and Ilymenophyllum alone ap- 
