208 rLOWERING AND ITS CONSEQUENCES. 



when cultivated in too rich a soil, often grow luxuriantly, but do not 

 blossom. The same thing is observed when our Northern fruit-trees 

 are transported into tropical climates. On the other hand, whatever 

 checks tliis continuous growth, without affecting the health of the 

 individual, causes blossoms to appear earlier and more abundantly 

 than they otherwise would. It is for this reason that transplanted 

 fruit-trees incUne to blossom the first season after their removal, 

 though they may not do so again for several years. A state of com- 

 parative rest seems needful to the transfoiination by which flowers 

 are formed. It is in autumn, or at least after the vigorous vegeta- 

 tion of the season is over, that our trees and shrubs, and most peren- 

 nial herbs, form the flower-buds of the ensuing year. 



375. The requisite annual season of repose, which in teiiiperate 

 chmates 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 there brought about, not by 

 cold, but by heat and dryness. The Cape of Good Hope, the 

 Canary Islands, and the southern and interior parts of California, 

 may be taken as illustrations. In the Canaries, the growing season 

 is from November to March, — the winter of the northern hemi- 

 sphere ; — ■ their winter also, as it is the coolest season, the mean 

 temperature being 66° Fahr. But the rains fall regularly, and 

 vegetation is active ; while in summer, from April to Octobei-, it 

 very seldom I'ains, and the mean tempei'ature is as high as 73°. 

 During this dry season, when the scorching sun reduces the soil 

 nearly to the dryness and consistence of brick, ordinary vegetation 

 almost completely disappears ; and the Fig-Marigolds, Euphorbias, 

 and other succulent plants, which, fitted to this condition of things, 

 alone remain green, not unaptly represent the Firs and other ever- 

 greens of high northern latitudes. The dry heat there brings about 

 the same state of vegetable repose as cold with us. The roots and 

 bulbs then lie dormant beneath the sunburnt 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 dimin- 

 ished temperature, just as with us by heat ; and the ready-formed 

 flower-buds are suddenly developed, clothing at once the arid 

 waste with a profusion of blossoms (194). The vegetation of such 

 regions consists mainly of succulents, which are able to live through 

 the drought and exposure ; of bulbous plants, which run through 

 their course before the drought becomes severe, then lose their 



