CHAPTER XIX. 



OV RESTING. 



A GABDENER is Said to rest a plant when he exposes it to a 

 condition in which it cannot grow, aud which is analogous to 

 its winter state. For many parts of gardening, especially what 

 relates to forcing, and the management of exotic plants, this is 

 a subject of the first importance. 



If we look over the different climates of the world, we shall 

 find that in each there are a season of growth, and a season in 

 which vegetation is more or less suspended; and that these 

 periodically alternate, with the same regularity as our summer 

 and winter. I do not know that there is in nature any excep- 

 tion to this rule : for even in the Tierra templada of Mexico, 

 where it is said that, at the height of 4000 to 5000 feet, there 

 constantly reigns the genial climate of spring, which does not 

 vary more than 8° or 9°, intense heat and excessive cold being 

 alike unknown, and the mean temperature varying from 68° to 

 70°, we cannot suppose that, even in that favoured region, a 

 season of repose is wanting ; for it is difficult to conceive how 

 plants can exist, any more than animals, in a state of incessant 

 excitement. Indeed, it is pretty evident that these countries 

 have a period when vegetation ceases ; for Xalapa belongs to the 

 Tierra templada, and we know that the Ipomoea purga, an 

 inhabitant of its woods, dies down annually like our own 

 Convolvuli. We also know that Jonquils, Hyacinths, and 

 Tnhps when grown in the Bahamas, where they are unable to 

 take the rest which is natural to them, refuse to flower. 



But, although aU plants have naturally a season of repose, 

 their winter is not in all cases cold. In the topics it is marked 



