EXOTIC FLOWERS AND PLANTS. 191 



or only to flower once in the year, there can be 

 no doubt; because the heat in the air of the 

 house will be sufficiently imparted to the soil in 

 it. And though this custom may have been only 

 accidentally adopted from what was found ne- 

 cessary for pines, yet it need not be persisted 

 in, except for those or other fruits. Even its 

 necessity for fruits has been doubted ; but such 

 doubts are injudicious, because, in the case of 

 fruit, we must not only provide the necessary 

 temperature for their existence, but must also 

 force them to yield their fruit in the shortest 

 time possible, to save expense and trouble. This, 

 therefore, should be the rule, that with pines, 

 mangoes, annonas, bananas, mangosteens, &c. 

 the roots require to be excited by heat as much 

 as, and perhaps even more than, the flowers and 

 foliage ; but for the other common inmates of a 

 hot-house, they do very well without, especially 

 if the heat of steam or hot water be provided. 



Collections of hot-house plants are first formed 

 by purchases from commercial houses, or from 

 seeds or plants imported from their native places 



