IO4 ORCHIDS. 



must likewise be comparatively recent : indeed no fossil 

 Orchid has ever been discovered, although ferns, with 

 which in these days Orchids are invariably associated, 

 have been found in countless myriads in the paleozoic 

 strata. 



About ten years since continued failure in the cultiva- 

 tion of many new Granadian and Peruvian Orchids, led to 

 the suspicion that both the theory and practice of culture 

 was fundamentally wrong, and experiments were tried in 

 varying the temperature, which met with partial success. 

 The fault still was, that too much heat was given, and 

 often too little moisture ; consequently, the finest species 

 dwindled day by day, flowering poorly, if at all, and 

 finally were lost to cultivation. 



It was in the collection of Linden that the first de- 

 cided move was .made towards cool treatment, and the 

 first decided triumph achieved, and there it was that the 

 rare and beautiful Odontoglossums figured in " Pesca- 

 toria," flowered for the first time. 



In growing plants under the " cool treatment " the 

 house should be low and small, and should be either a 

 lean-to facing the north, or a well shaded span-roof. 

 The temperature should be as equable as circumstances 

 will permit, that is to say, during the day-time in winter 

 it should not fall below 60, while during the day-time in 

 summer, the less it rises above 70 the better. In the 

 night, of course, the temperature will fall considerably, 

 and even if it sink below 50 no harm will be done, and 

 many of the finest Odontoglossums will thrive at a mini- 

 mum temperature of 35. 



Experience has shown that the East Indian house, or 

 a temperature averaging from a winter minimum of 60 



