SELAGINELLA. 
229 
and development day by day — would contribute to a 
thorough knowledge of them and their differences. We 
offer a few suggestions and hints as to their cultivation. 
A small Wardian case, a northern aspect, a few blocks 
of sandstone, and some peat soil, are the materials that 
would be required. The Wardian case, while protecting 
them in some degree from the changes of temperature 
incidental to a lowland climate, would secure to them a 
constantly moist atmosphere, which they all prefer. The 
interior should be fitted up with an artificial mound of 
^^rockwork,"" made of lumps of soft sandstone, in the 
disposal of which there will be an opportunity for the 
display of much taste. At the base of the ‘^rockwork"' 
there should be a little pond of water, in which Isoetes 
Pilularia might be cultivated. A portion of the peaty 
soil should be introduced into the interstices of the rock- 
work, and about its base on the margins of the water. 
In the former situations the smaller and alpine species, 
such as alpinurriy annotinum^ and selaginoides, should be 
planted ; while on the lower and damper parts should be 
placed such as inundatum and clamtum. 
The soil employed should be peat earth intermediate in 
texture between the spongy and the unctuous kinds ; that 
