SELAGINELLA. 229 



and development day by day — would contribute to a 

 thorough knowledo;e of them and their differences. We 

 offer a few su2;o;estions 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 tlie 

 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 and 

 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 alpinum, annotinum, and selaginoides, should be 

 planted ; while on the lower and damper parts should be 

 placed such as inundatum and clavatum. 



The soil employed should be peat earth intermediate in 

 texture between the spongy and the unctuous kinds ; that 



