73 



onep, as the former are especially impatient of too much artificial heat. 

 Some crchidists are, however, now advocating higher temperatures 

 for these plants, giving the minimum as 50, or preferably 55 ; but 

 something depends upon the situation and style of house, for very 



food plants are grown where the temperature in winter is allowed to 

 all to 45 or even 40. 



TEMPERATURE. Since Orchids are found in such widely varied 

 districts it can be readily understood that with other conditions the 

 temperatures to which they are exposed differ considerably. In 

 cultivation, however, we are compelled to group the plants as nearly 

 as possible according to their respective requirements as regards 

 heat. Nurserymen and wealthy amateurs who have extensive 

 collections commonly devote houses to each of the larger genera, 

 structures being appropriated to Cattleyas, Lselias, Dendrobinms, 

 Cypripediums, Phalaennpses, Vandas, Odontoglossums, Masdevallias, 

 &c. ; but in smaller establishments it is seldom that more than three 

 houses can be used for Orchids alone ; and all that need the protection 

 of glass can be readily grown in those by regulating the temperature. 

 Thus the warmest house (day temperature of the year 65 C to 80) 

 would contain the Orchids from the tropical regions of the Old World, 

 especially the East Indies, the Malayan Archipelago, and adjoining 

 countries on the main land. An intermediate house (day temperature 

 of the year 60 to 75) would be used for the tropical Orchids of 

 America, comprising the Cattleyas, Lselias, and other plants from 

 Brazil and the lower parts of Mexico. The third house (day 

 temperature of the year 50 to 65) would answer for most of the 

 Odont' glossums and Matdevallias, with other plants from high 

 regions in tropical countries. All indoor Orchids can be satisfactorily 

 grouped in these three divisions, and in the following notes they will 

 be referred to as the warm house, intermediate house, and cool house. 

 It should be observed that in general practice there has been a great 

 reduction in the temperatures for Orchids, and some very experienced 

 growers, like Dr. H. Paterson of Bridge of Allan, rely exclusively 

 upon sun heat for the higher summer temperatures, and at that season 

 frequently have no artificial heat. There can be no doubt that 

 highly heated houses during the winter when we are compelled to 

 rest the majority of our Orchids is exceedingly injurious, weakening 

 them and rendering them precocious in flowering, and much more 

 liable to the attacks of insects. If strong growth is made and wtll 

 ripened under plentiful sun heat and free ventilation Orchids will 

 endure a much lower temperature than is usually supposed, and wil 

 be far more satisfactory than when roasted, ca they were in the eaily 

 stages of their culture. As a general guide to the temperature of 

 the year for Orchid houses the following table, which w r as included 

 in the paper read by Mr. James O'Brien at the Orchid Conference 

 in 1885, is very useful : 



