75 



It may be observed that if a few particulars are known respecting 

 the habitat of newly introduced Orchids it is not difficult to provide 

 for their requirements. The first point is to ascertain the country and 

 latitude, then the altitude, and finally any other circumstances, such 

 as whether the position is exposed or shaded, and in the case of 

 terrestrial Orchids the character of the soil in which they are growing. 

 The rule usually given for calculating the depression of temperature 

 in ascending mountains is to allow a fail of 1 Fahr. for every 300 

 to 350 feet of altitude, but the depression is more rapid in the higher 

 regions. Thu in the tropics, where the temperature at the ground level 

 might be 80, at an eleva'ion of 6 to 7000 feet would be estimated to 

 be 55 to 60. This is, however, necessarily influenced to a great 

 extent by the position of the land, whether sloping towards the sun or 

 not, also whether the mountains are near the sea or inland ; but an 

 approximate idea may be gained of what the plants need. 



CULTURAL MATERIALS. 



Good results in plant culture are largely dependent upon the soil 

 employed for them, and too little attention is often paid to the 

 subject. For Orchids it is particularly important, and a few notes on 

 the principal materials necessary may be useful. 



PEAT. This is a well-known substance used extensively for hard- 

 wooded plants, Heaths, &c. ; and for the majority of Orchids it is 

 indispensable. It varies greatly in its character, depending chiefly 

 upon the nature of the soil where it is obtained and the roots of which 

 it is composed. In some places it consists mainly of the roots of 

 grasses and a black soil derived from the decomposition of vegetation, 

 and is then termed bog peat ; in others it chiefly comprises wild 

 Heath roots and finer grasses, and is found in higher districts, a third 

 kind being mainly formed of Fern roots and rhizomes, both the last 

 named containing a varying proportion of light brownish soil from 

 the farther decomposition of the roots, &c. These are the principal 

 kinds, but there are many intermediate grades. The bog peat, which 

 also generally contpins a proportion of sand, is most suitable for 

 Heaths and similar plants ; the second kind is used for Ferns, and 

 the third is the best for Orchids. For these plants it must abound in 

 fibre, and the smaller particles should be shaken out before it is used, 

 when it can be broken up into pieces of various sizes according to the 

 plants for which it is to be employed, but never very small. If a 

 quantity is procured at one time it must be stacked where it will not 

 be exposed to the wet, and yet not in a hot position where it will 

 become too much dried. When ordering peat intending purchasers 

 should state that it is required for Orchids, and the dealers will then 

 know whit to supply. 



SPHAGNUM. The moss used for Orchids consists mainly of 

 Sphagnum obtusifolium, but S. squarrosum, 8. acutifolium and 



