48 EVERGREENS. TEASEL. 



EDWARD. 



Then do they never change their leaves ? 



MOTHER. 



They change them once in the course of a year, 

 but the plant is always green, because the young 

 leaves come out before the old ones decay. Leaves 

 are usually Deciduous, that is to say, they last only 

 one season; but there are a few plants whose leaves 

 last two or three, and sometimes as long as four 

 years. 



In the East and West Indies almost all the 

 trees are evergreen, and have broad leaves ; but 

 most of the trees in our cold regions cast their fo- 

 liage every year; and such as do not have narrow 

 and sharp leaves. It is supposed that if the leaves 

 were broader, the snow which falls during the 

 winter would collect among them, and often break 

 the branches by its weight; their slenderness pre- 

 vents this, by allowing the snow to pass between 

 them. This precaution would be unnecessary in 

 India, and other countries where snow is not 

 known. 



I will now tell you of a few other plants in the 

 class Tetrandria. The clothiers' Teasel, Dip'sa- 

 cus fullo'num, is very much cultivated in the west 

 of England, for the use of cloth manufactories. 

 The heads are fixed to the edge of a large broad 

 wheel, which is kept turning, while the cloth is held 



