THE MOST USEFUL ORCHIDS 129 



one potsherd concavely over the drainage hole, and cover this to 

 one-third or one-half the pot's depth w^ith smaller potsherds or 

 crocks, but the modern method is to place a large crock in the 

 bottom of the pot and cover it to the depth of an inch or so with 

 small pieces of the rhizomes of the common Bracken fern. These 

 rhizomes are found in the turves of peat supplied by the nursery- 

 men, or they may be purchased separately, provided one has no 

 access to a Common or Heath or Woodland where this most 

 common of British ferns is abundant. The rhizomes must be 

 sterilized before use, otherwise they may grow and cause trouble. 



Sterilization is easily managed by putting the rhizomes in a 

 very hot oven long enough to kill them, or by placing a quantity 

 in a copper full of boiling water for a few minutes, and then 

 spreading them out to dry. 



A great deal might be written about the material or materials 

 in which the Odontoglossums are to root. The fibrous portion of 

 the peat cut from Moor or Common, and consisting chiefly of the 

 fine Heather and Bracken roots, was long regarded as the only 

 suitable material for Odontoglossums, and there are still many 

 successful growers who use nothing else, saving always the addition 

 of Sphagnum moss. But Polypodium, Osmunda, and other fern 

 fibres have been used with excellent results in place of peat during 

 recent years, while the tcrre brnycre of the Belgians has had a great 

 vogue on the Continent. Half-decayed leaves (not leaf mould as 

 we generally understand it), is now very largely used, and in the 

 hands of numerous skilful cultivators it has proved an eminently 

 successful potting material. It consists of Oak or Beech leaves, 

 collected as soon as they have fallen in the Autumn, and stored 

 free from other leaves, soil, or sweepings. If heavy rains are kept 

 from them, they will be in good condition for use the following 

 Autumn, and the only preparation necessary will consist of lightly 



