96 THE BOOK OF ORCHIDS 



with plenty of holes in it, or a teak basket answers the 

 purpose admirably. It delights in having sphagnum 

 moss growing luxuriously around the base of the pseudo 

 bulbs ; and a light position in the cool house will suit its 

 cultural requirements. When seen in bloom this species 

 is always greatly admired. O. retusum is a rare and 

 distinct Odontoglossum, and when grown strong the 

 inflorescence includes over a hundred flowers, with 

 orange-red sepals and petals, and orange-coloured lip. 



Oncidium 



A large genus of epiphytal Orchids inhabiting the 

 whole of Central America from Mexico and the West 

 Indies to the southern parts of Brazil. Over 250 species 

 have been described, and, besides these, numbers of 

 others are known to exist in various parts of that vast 

 region. The difference in the conditions under which 

 Oncidiums grow in their native habitats is very great. 

 Some occur only in the hot moist valleys of the most 

 tropical parts of America, and are found luxuriating 

 under very varied conditions, some in bright sunlight, 

 and others in dense shade ; many are found on the 

 Cordilleras of Peru and Columbia at altitudes ranging 

 from 5000 to 9000 feet, and a few ascend to near the 

 snow line on the Andes where frost is frequent. If a 

 representative collection of Oncidiums is to be formed, 

 the grower should ascertain if possible the climatic con- 

 ditions under which they grow in their native country. 

 This would afford him excellent indications as to the 

 treatment each species should receive when transferred 

 to his Orchid houses. Unfortunately I am unable to 

 enumerate anything like a complete list of the various 

 species and their cultural requirements here, but as a 

 guide to inexperienced cultivators the following remarks 

 on the different sections may prove useful : Taking first 



