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PREFACE TO 8EC0I\^D EDITION. 



The collection now includes a larger number of genera 

 (220) than in 1896, and a somewhat larger number of 

 species (1850) including well marked hybrids. Only 

 varieties of botanical interest have been enumerated. What 

 may be called " garden hybrids," the number of which 

 now known may be counted by hundreds, are of little 

 scientific interest, though commercially some of them are 

 of great value. They ai-e only sparingly representeil 

 at Kew. 



The Kew collection has much improved in health 

 since the reconstruction in 1898 of the houses (Nos. 13 

 and 14) accessible to the public. These were originally 

 erected in 1868 and were 13 feet high. They have now 

 been reduced to 9 feet. This has the double advantage 

 of bringing the plants more closely to the light as well as 

 to the eyes of visitors. The houses have also been 

 divided into four compartments, the conditions of Avhich 

 vary in regard to temperature and atmospheric moisture. 

 In 1901 a small pit was adapted for the cultivation of 

 Dendrobiums. 



A few changes in nomenclature have become necessary, 

 the most important being the separation of species formely 

 included under Gnttleya labiata and the breaking up of 

 the genus Cypripedium. 



W. T. T. D. 

 Kew, March, 1904. 



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