Introduction^ etc. 37 



and the Annuals, may be considered practically 

 hardy, inasmuch as they only require to be raised 

 in warm or cool frames, or even (some of them) in 

 the open air. When once planted out for the 

 summer, they give but little further trouble. 



In the next group may be placed the tender 

 greenhouse kinds ; long-lived subjects, like the 

 Dracaenas, American Aloe, etc., which thrive in 

 greenhouses or conservatories in winter, and are 

 great ornaments there, and which may be placed 

 in the open air in summer without the least injury. 

 Next to the hardy group, this is the most im- 

 portant, from the fact that the subjects are effective 

 at all seasons of the year, and useful indoors as 

 well as without. They also, unlike the following, 

 may be enjoyed by every one who possesses any 

 kind of a cool glazed structure ; and even, in some 

 cases, this is not needed, for I have seen some very 

 fine specimens of Agave americana kept in a large 

 entrance hall in winter, and put out of doors in 

 May to be taken in again in October. 



Lastly, we have the least important group of all, 

 and happily also the most costly, viz., those plants 

 which must be kept through the winter and spring 

 in warm stoves, such as Ferdinanda, Solanum, etc. 

 Considering the vast number of hardy and half- 



