CHAP. XV VILLA GARDENING 227 



things, will retain their flowers much longer in the equable 

 temperatiu'e of the north house than in the sunshine. Azaleas 

 and many of the New Holland plants may have their season much 

 prolonged by being kept cool in the spring in a house where the 

 sun cannot reach them to excite the blossom buds. In fact, no 

 exhibitor seeking distinction can do Avithout a retarding house to 

 make his early and late plants meet at the right time. All the 

 family of Lilies succeed admirably in the north house in summer, 

 theii" flowers lasting much longer away from the sun's exciting 

 influence. But I need not refer to it at greater length, as the 

 value of retarding houses will be easily understood by all plant- 

 .trrowers. 



CHAPTER XV 



Cool Orchids. — ^ These may be divided into several classes, 

 according to the conditions under Avhich they grow naturally, and 

 the couutries whence they come. Thus the Mexican Orchids 

 succeed in a low temperature, 45° to 50° being quite high enough 

 at night in winter, with a rise of from 7" to 10" in the daytime 

 from fire heat alone. But the Mexican Orchids require a drier 

 atmosphere and a freer circulation of air than cool Orchids generally 

 do — such, for instance, as those which inhabit the higher regions 

 of Peru — and this involves the application of more artificial heat 

 in order to warm the air introduced. Though there are hundreds 

 of sjiecies of Orchids from Mexico and elsewhere belonging to the 

 families of Epidendrum, Bletia, Dendrobium, Oncidium, Maxillaria, 

 Lycaste, Odontoglossum, etc., that will tiom-ish in a night 

 temperatm-e under 50° in winter, which is not much higher than 

 a warm greenhouse temperatiu'e, yet there are Orchids with cooler 

 taste still than these. The Peruvian Odontoglots, many of the 

 Oncidiums from the higher mountain ranges, and others of similar 

 habit and capacity, only require in winter to be secm-ed from frost. 

 Even the day temperature need not exceed 50° if fire heat alone 

 has to be used to produce it, for too much artificial heat desiccates 

 the moisture and dries the atmosphere much. A low tempera- 

 ture laden with moisture at all times, winter and summer, day and 

 night, is necessary to suit this class of Orchids. There will of 

 course be fluctuations in the surrounding conditions, but nothing 

 approaching forcing should ever be attempted, because it will surely 

 lead to the plants becoming unhealthy. Sometimes one is anxious 

 to push on a slow-growing plant, but an increase of temperature 

 will certainly defeat the object in view. The supply of moisture 



