THE BRITISH CLUB-MOSSES. 101 



sandstone, and some peat soil, are the materials that would 

 be required for their cultivation. The Wardian case, which 

 may be rude or polished, while protecting them in some 

 degree from the changes of temperature incidental to a low- 

 land climate, would secure to them a constantly moist at 

 mosphere, which they all prefer. The interior should be 

 fitted up with an artificial mound of " rockwork," made of 

 lumps of porous sandstone. At the base of the " rockwork" 

 a little pond or pool would provide a situation in which 

 Isoetes and Pilularia might be cultivated. In the interstices 

 Df the rockwork, the smaller and alpine species, such as 

 alpinum, annotinum, and selaginoides, should be planted; 

 while about its base on the margins of the water, and con- 

 sequently 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 

 used among the rockwork may have in addition a portion of 

 the sandstone pounded and intermixed with it. That used 

 for inundatum in the lower part of the case will not require 

 this intermixture, and, in fact, will be the better with- 

 out it. 



All parts of the soil should be kept rather moist than 

 otherwise, by the application of fresh water occasionally; 

 but as the confinement of the atmosphere in the damp state, 

 in a close case, might tend to produce decay in some parts of 

 the vegetable tissues, the little door or hinged sash may from 

 time to time be left open for a few hours, in order that the 

 stagnant moisture may be carried off, when a fresh supply 

 will be doubly grateful to the plants. 



It must be recollected, that the soil will be exposed to 

 very slight drying influences, and can, therefore, never re- 

 quire to be very copiously supplied at any one time ; the 

 proper course being, rather to ventilate frequently, say once a 

 week, in order to carry off the accumulated dampness, and 

 then by a moderate fresh supply to produce a continued 

 change of the watery element. For the same reason, and to 

 prevent the souring of the soil, which always takes place 

 more or less when it is in contact with stagnant water, an 

 outlet at the bottom of the case should be carefully pro- 

 vided, by which all the free water at least, which drains 

 through after the soil has been irrigated, may be removed as 

 it accumulates. 



As to aspect, the northern is decidedly the best, principally 

 for the reason that in such a situation the sun has less influ- 



