184 Of Flowering, and its Results. 



flowers are formed. It is in autumn, or at least after the 

 ous vegetation of the season is over, that our trees and shrub 

 and most perennial herbs, produce the flower buds of th' 

 ensuing year. 



The requisite annual season of repose, which in temperat 

 climes is attained by the lowering of the temperature in autumn 

 and winter, is scarcely less marked in many tropical countries 

 where winter is unknown. But the result is brought about in 

 the latter case, not by cold, but by excessive heat and dryness 

 The Cape of Good Hope, or the Canary Islands may be taken 

 as illustrations. In the Canaries, the growing season is from 

 November to March — the winter of the northern hemisphere— 

 their winter also, as it is the coolest season. But the rains fall 

 regularly, and vegetation is active ; while in summer, from 

 April to October, it very seldom rains, and the mean tempera- 

 ture is as high as 73°. During this dry season, when the 

 scorching sun reduces the soil nearly to the dryness and consis- 

 tency of brick, ordinary vegetation almost completely disappears, 

 and the Fig-Marigolds, Euphorbias, and other succulent plants 

 fitted to this condition of things, alone remain green, not unaptly 

 representing the Firs and other evergreens cf high northern 

 latitudes. The dry heat there brings about the same state of 

 Vegetable repose as cold with us. The roots and bulbs then 

 he dormant beneath the sun-burnt crust, just as they do in our 

 frozen soil. When the rainy season sets in, and the crust is 

 softened by moisture, they are excited into growth under a 

 diminished temperature, just as with us by heat ; and the 

 ready formed flower buds are suddenly developed, and at 

 once clothe the arid waste with a profusion of blossoms. 

 This season of interruption to growth, produced either by cold 

 or dryness, occurs in a more or less marked degree, through 

 every part of the world. 



These considerations explain the operations of forcing plants, 

 by which we are enabled to obtain in winter the flowers and 

 fruits of summer. The gardener accomplishes these results 

 principally by skilful alterations of the natural period of 

 repose. He gives the plant an artificial period of rest by 

 dryness at the season when he cannot command cold, and then, 

 by the influence of heat, light and moisture, which he can 



